Lalic Lab



The following is a collection of problems in organic and organometallic chemistry collected by Boydston, Lalic, and Michael groups.

The keywords for each problem can be made visible by selecting the space immediatly following the "Keywords:" heading.
The collection can be searched for a particular keyword using CTRL+F function of your web browser.

For a list of keywords currently in the collection click here
For the chemdraw template click here

For the powerpoint from the latest meeting click here

Problem 94. Provide a mechanism for the following transformations.
Contributor: AJ Boydston
Source: Nature 2012, 490, 208.
Keywords: Diels-Alder, cycloaddition


Problem 93. Provide a mechanism for the following transformation.
Contributor: AJ Boydston
Source: Org. Lett. DOI: 10.1021/ol400317v.
Keywords: photoredox catalysis


Problem 92. Provide a mechanism for the following transformations.
Contributor: AJ Boydston
Source: Org. Lett. 2013, 15, 914.
Keywords: Shapiro reaction, rearrangement


Problem 91. Provide a mechanism for the following transformations.
Contributor: AJ Boydston
Source: Org. Lett. 2013, 15, 476.
Keywords: Piancatelli rearrangement


Problem 90. Provide a mechanism for the following transformation.
Contributor: AJ Boydston
Source: Angew. Chem. Int. Ed. 2013, 52, 4016.
Keywords: cyclopropanation


Problem 89. Provide products and mechanisms for the following reactions.
Contributor: M Larsen
Source: Eur. J. Org. Chem. (DOI: 10.1002/ejoc.201201516).
Keywords: ene-yne metathesis


Problem 88. Provide a mechanism for the following transformation.
Contributor: AJ Boydston
Source: Chem. Commun. 2013, 49, 1193.
Keywords: sigmatropic rearrangement


Problem 87. Provide the product and a plausible mechanism for the following transformation
Contributor: AJ Boydston
Source: Org. Lett. 2013, 15, 602.
Keywords: Lossen rearrangement


Problem 86. Provide an explanation for the observed product ratios.
Contributor: AJ Boydston
Source: Org. Lett. 2012, 14, 256.
Keywords: organocatalysis, cyclization


Problem 85. Propose an explanation for the catalytic activity.
Contributor: AJ Boydston
Source: J. Am. Chem. Soc. 2012, 134, 12693.
Keywords: photochemical, organocatalysis, photoswitch


Problem 84. Provide a mechanism for the following transformation.
Contributor: AJ Boydston
Source: Angew. Chem. Int. Ed. 2011, 50, 4445.
Keywords: Witkop reaction, photochemical, cytclization, electron transfer


Problem 83. Provide a mechanism for the following transformation.
Contributor: AJ Boydston
Source: J. Org. Chem. 2012, 77, 6327.
Keywords: cyclization


Problem 82. Provide a mechanism for the following transformation.
Contributor: G Lalic
Source: Tetrahedron Lett. 1968, 5609.
Keywords: radical


Problem 81. Provide a mechanism for the following transformation.
Contributor: G Lalic
Source: Tetrahedron Lett. 1992, 2157.
Keywords: radical


Problem 80. Provide a mechanism for the following transformation.
Contributor: G Lalic
Source: Tetrahedron Lett. 1993, 127.
Keywords: radical


Problem 79. Provide a mechanism for the following transformation.
Contributor: G Lalic
Source: J. Org. Chem. 1990, 55, 5181.
Keywords: radical


Problem 78. Provide a mechanism for the following transformation.
Contributor: G Lalic
Source: J. Am. Chem. Soc. 1990, 112, 5601.
Keywords: radical


Problem 77. Provide a mechanism for the following transformation.
Contributor: G Lalic
Source: Chem. Commun. 1988, 81.
Keywords: radical


Problem 76. Provide a mechanism for the following transformation.
Contributor: G Lalic
Source: Tetrahedron Lett. 1983, 15.
Keywords: radical


Problem 75. Provide a mechanism for the following transformations.
Contributor: G Lalic
Source: J. Org. Chem. 1974, 39, 3456.
Keywords: radical


Problem 74. Provide a mechanism for the formation of all the products. How would you supress the formation of the byproducts?
Contributor: G Lalic
Source:
Keywords: radical


Problem 73. Provide a mechanism for the following transformations.
Contributor: G Lalic
Source: J. Am. Chem. Soc. 2013, 135, 66.
Keywords: CH activation


Problem 72. Provide a mechanism for the following transformations.
Contributor: G Lalic
Source: J. Am. Chem. Soc. 2007, 129, 10096.
Keywords: iminium


Problem 71. Provide a mechanism for the following transformations.
Contributor: G Lalic
Source: J. Am. Chem. Soc. 2011, 133, 6411.
Keywords: radical addition


Problem 70. Provide a mechanism for the following transformations.
Contributor: G Lalic
Source: J. Am. Chem. Soc. 2011, 133, 18018.
Keywords: cycloisomerization


Problem 69. Provide a mechanism for the following transformations.
Contributor: G Lalic
Source: J. Am. Chem. Soc. 2008, 130, 6918.
Keywords: electrocyclic reaction


Problem 68. Provide a mechanism for the following transformations.
Contributor: G Lalic
Source: J. Am. Chem. Soc. 2012, 134, 9078.
Keywords: carbanion


Problem 67. Provide a mechanism for the following transformations.
Contributor: G Lalic
Source: J. Am. Chem. Soc. 2008, 130, 8602.
Keywords: carbene, sigmatropic rearrangement


Problem 66. Provide a mechanism for the following transformations.
Contributor: AJ Boydston
Source: J. Am. Chem. Soc. 2011, 133, 14785.
Keywords: Tsuji-Trost allylation, Claisen condensation


Problem 65. Propose a synthesis of the target molecule from each starting material.
Contributor: AJ Boydston
Source: J. Org. Chem. 2012, 77, 9422.
Keywords: synthesis


Problem 64. Provide a mechanism for the following transformations.
Contributor: AJ Boydston
Source: Org. Lett. 2012, 14, 264.
Keywords: Eschenmoser-Tanabe fragmentation


Problem 63. Provide a mechanism for the following transformations.
Contributor: AJ Boydston
Source: Tetrahedron 1993, 49, 10501.
Keywords: aldol,Grob fragmentation


Problem 62. Provide a mechanism for the following transformations.
Contributor: G. Lalic
Source: Org. Lett. 2012, 14, 126.
Keywords: retro 2+2, 4+2, cheletropic reaction, 3+2


Problem 61. Provide a mechanism for the following transformations. Provide a structure of A.
Contributor: G. Lalic
Source: J. Am. Chem. Soc. 2012, 134, 7286.
Keywords: rearrangement


Problem 60. Provide an explanation for the following observation.
Contributor: G. Lalic
Source: J. Am. Chem. Soc. 2012, 134, 7262.
Keywords: nitrene, CH activation


Problem 59. Provide a mechanism for the following transformation.
Contributor: G. Lalic
Source: J. Am. Chem. Soc. 2012, 134, 7262.
Keywords: nitrene, CH activation


Problem 58. Provide a mechanism for the following transformation. Provide an explanation for the observed diastereoselectivity.
Contributor: G. Lalic
Source: J. Am. Chem. Soc. 2012, 134, 6928.
Keywords: 1,2 sigmatropic rearrangement, electrophilic activation


Problem 57. Provide a mechanism for the following transformation. The proposed mechanism should provide an explanation for the selectivities observed in the two reactions.
Contributor: G. Lalic
Source: Org. Lett 2012, 14, 2940.
Keywords: radical, oxidation


Problem 56. Provide a mechanism for the following transformation. The proposed mechanism should provide an explanation for the selectivities observed in the two reactions.
Contributor: G. Lalic
Source: J. Am. Chem. Soc. 2012, 134, 8260.
Keywords:


Problem 55. Provide a mechanism for the following transformation.
Contributor: AJ Boydston
Source: Org. Lett. 2011, 13, 6034.
Keywords: oxidation


Problem 54. Provide a mechanism for the following transformation.
Contributor: AJ Boydston
Source: J. Phys. Chem. A 2010, 114, 13086.
Keywords: Knoevenagel-Doebner, decarboxylation, elimination, olefination


Problem 53. Provide a mechanism for the following transformation.
Contributor: AJ Boydston
Source: Angew. Chem. Int. Ed. 2012, 51, 513.
Keywords: ligation, oxaziridine, decarboxylation


Problem 52. Provide a mechanism for the following transformations.
Contributor: F. Michael
Source: Angew. Chem. Int. Ed. 2012, 51, 8816–8820.
Keywords: radical addition


Problem 51. Provide a mechanism for the following transformation.
Contributor: F. Michael
Source: Org. Lett., 2012, ASAP, DOI: 10.1021/ol302077n
Keywords: ylide


Problem 50. Provide a mechanism for the following transformation.
Contributor: F. Michael
Source: J. Am. Chem. Soc., 2012, 134 (33), 13577–13579.
Keywords: Shapiro


Problem 49. Propose a synthesis.
Contributor: F. Michael
Source: J. Am. Chem. Soc., 2012, 134 (33), 13577–13579.
Keywords: synthesis


Problem 48. Provide a mechanism for the following transformations.
Contributor: G. Lalic
Source: Org. Lett. 2012, 14, 58.
Keywords: Prins


Problem 47. Provide a mechanism for the following transformations.
Contributor: G. Lalic
Source: Org. Lett. 2012, 14, 122.
Keywords: Cope rearrangement


Problem 46. The following is the key step in De Brabander’s synthesis of Berkelic acid. Please provide a mechanism.
Contributor: G. Lalic
Source: J. Am. Chem. Soc. 2009, 131, 11350.
Keywords: Ortho quinone methide


Problem 45. Provide a mechanism for the following transformations.
Contributor: G. Lalic
Source: Org. Lett. 2012, 14, 18.
Keywords: Ortho quinone methide


Problem 44. Provide a mechanism for the following transformations.
Contributor: AJ Boydston
Source: J. Org. Chem. 2012(DOI:10.1021/jo300872y)
Keywords: Prins, Prins-Pinacol


Problem 43. Provide a mechanism for the following transformation and rationalize the disparate reactivity of the diastereoisomers.
Contributor: AJ Boydston
Source: Org. Lett. 2012, 14, 3604.
Keywords: Schmidt


Problem 42. Provide a mechanism for the following transformation.
Contributor: AJ Boydston
Source: Org. Lett. 2012, 14, 3604.; J. Am. Chem. Soc. 1977, 99, 7601.
Keywords: epoxidation, Corey-Chaykovsky


Problem 41. What can be inferred about the relative rates of initiation, propagation, and termination based on the kinetic data for the shown polymerization reaction? What additional conclusions could be drawn from either braoad or narrow PDIs?
Contributor: AJ Boydston
Source: Synlett 2007, 10, 1573.; J. Am. Chem. Soc. 2012, 134, 9163.
Keywords: polymerization


Problem 40. Provide the structure of the resulting polymers.
Contributor: AJ Boydston
Source: Synlett 2007, 10, 1573.; J. Am. Chem. Soc. 2012, 134, 9163.
Keywords: polymerization


Problem 39. N-Carboxyanhydrides (NCAs) are useful monomers for ring-opening polymerizations to synthesize polypeptoids. Provide a mechanism for the first step in the synthesis of the NCA.
Contributor: AJ Boydston
Source: Synlett 2007, 10, 1573.; J. Am. Chem. Soc. 2012, 134, 9163.
Keywords: decarboxylation


Problem 38. Complete the synthetic scheme.
Contributor: F. Michael
Source: J. Am. Chem. Soc. 2010, 132, 15790.
Keywords: cyclopropanation, allylation, Cope rearrangement


Problem 37. Propose a mechanism for the following transformation.
Contributor: F. Michael
Source: Eur. J. Org. Chem. 2002, 791.
Keywords: Diels-Alder, electrocyclic reaction


Problem 36. Propose a mechanism for the foloowing transformation and identify A.
Contributor: F. Michael
Source: J. Am. Chem. Soc. 2012, 134, 11964.
Keywords: Cope rearrangement, carbanion, Diels-Alder


Problem 35. Propose a mechanism for the foloowing transformation. What byproducts would you expect based on your mechanism?
Contributor: F. Michael
Source: J. Am. Chem. Soc. 2011, 133, 5784.
Keywords: Suzuki coupling, p allyl metal complex


Problem 34. Provide a mechanism for the following transformation.
Contributor: G. Lalic
Source: J. Am. Chem. Soc. 2012, 134, 6924.
Keywords: 3+2 cycloaddition


Problem 33. In a recent total synthesis of Flinderol B, the authors reported the following transformations. Provide the mechanism for the formation of the two products.
Contributor: G. Lalic
Source: J. Am. Chem. Soc. 2012, 134, 6936.
Keywords: Diels-Alder, 3+2 cycloaddition


Problem 32. Provide a mechanism for the following transformation.
Contributor: G. Lalic
Source: J. Am. Chem. Soc. 2012, 134, 4064 & J. Am. Chem. Soc. 2008, 130, 3645.
Keywords: electrocyclic reaction, CH activation


Problem 31. Provide an explanation for the observed selectivities. Your answer should include 3D drawings of all relevant TS.
Contributor: G. Lalic
Source: J. Am. Chem. Soc. 2012, 134, 6528.
Keywords: Curtius rearrangement


Problem 30. Provide a mechanism for the following transformation.
Contributor: G. Lalic
Source: J. Am. Chem. Soc. 2012, 134, 6528.
Keywords: Curtius rearrangement


Problem 29. Provide a mechanism for the following transformation. What is the role of the catalyst? What is the rate limiting step of the reaction? What is the product determining step of the reaction?
Contributor: G. Lalic
Source: Org. Lett. 2009, 11, 887
Keywords: Pictet–Spengler


Problem 28. Provide a mechanism for the following transformation.
Contributor: G. Lalic
Source: J. Am. Chem. Soc. 2012, 134, 1930.
Keywords: metal vinylidene


Problem 27. Provide a mechanism for the following transformation.
Contributor: G. Lalic
Source: J. Am. Chem.Soc. 2012, 134, 2504.
Keywords: hydride transfer, iminium


Problem 26. Provide a mechanism for the following transformation.
Contributor: G. Lalic
Source: Angew. Chem. Int. Ed. 2011, 50, 5932.
Keywords: carbene, metal carbenoid, cyclopropanation


Problem 25. Based on information presented in reactions A and B, provide a mechanism for transformation C.
Contributor: AJ Boydston
Source: Org. Lett. 2011, 13, 1678. and J. Am. Chem. Soc. 2002, 124, 9368.
Keywords: electrochemistry


Problem 24. Provide a mechanism for the following transformations. Provide the structure of product A.
Contributor: AJ Boydston
Source: J. Am. Chem. Soc. ASAP (10.1021/ja3030824)
Keywords: CH activation


Problem 23. Provide a mechanism for the following transformation.
Contributor: AJ Boydston
Source: Org. Lett. 2011, 13, 3667.
Keywords: Fischer Indol


Problem 22. Provide a mechanism for the following transformation.
Contributor: AJ Boydston
Source: Adv. Synth. Catal. 2012, 354, 1356.
Keywords: electrocyclic reaction, sigmatropic rearrangement


Problem 21. Provide a mechanism for the following transformation.
Contributor: G Lalic
Source: J. Am. Chem. Soc. 2011, 133, 20100.
Keywords: Cope elimination


Problem 20. Provide a mechanism for the following transformation.
Contributor: G Lalic
Source: Pure Appl. Chem. 2010, 82, 1353.
Keywords: cycloisomerization


Problem 19. Provide a mechanism for the following transformation.
Contributor: G Lalic
Source: Pure Appl. Chem. 2010, 82, 1353.
Keywords: cycloisomerization


Problem 18. Provide a mechanism for the following transformation and the structure of A.
Contributor: G Lalic
Source: Chem. Commun. 2007, 2633.
Keywords: Pauson-Khand, decarbonylation


Problem 17. Provide a mechanism for the following transformation.
Contributor: G Lalic
Source: J. Am. Chem. Soc. 2007, 129, 1874.
Keywords: cycloisomerization


Problem 16. Provide a mechanism for the following transformation.
Contributor: G Lalic
Source: J. Am. Chem. Soc. 1994, 116, 4268.
Keywords: cycloisomerization


Problem 15. Provide a mechanism for the following transformation.
Contributor: F Michael
Source: J. Am. Chem. Soc. 2012, 134, 6936.
Keywords: Pictet–Spengler, iminium


Problem 14. Provide a mechanism for the following transformation.
Contributor: F Michael
Source: J. Am. Chem. Soc. 2009, 131, 8798.
Keywords: acylketene


Problem 13. Provide a mechanism for the following transformation. Explain the stereochemistry.
Contributor: F Michael
Source: Org. Lett. 2011, 13, 1490.
Keywords: rearrangement


Problem 12. Provide a mechanism for the following transformation. Explain the stereochemistry.
Contributor: F Michael
Source: J. Am. Chem. Soc. 2012, 134, 7570.
Keywords: rearrangement


Problem 11. Provide a mechanism for the following transformation. Explain the stereochemistry.
Contributor: F Michael
Source: Org. Lett. 2011, 13, 1490.
Keywords: rearrangement


Problem 10. Provide a mechanism for the following transformation
Contributor: AJ Boydston
Source: J. Am. Chem. Soc. 1997, 119, 2965.
Keywords: radical


Problem 9. Provide a mechanism for the following transformation
Contributor: AJ Boydston
Source: J. Org. Chem. 1988, 53, 3351.
Keywords: cycloaddition


Problem 8. Provide a mechanism for the following transformation
Contributor: AJ Boydston
Source: Org. Lett. 2011, 13, 4790.
Keywords: organocatalysis


Problem 7. Provide a mechanism for the following transformation
Contributor: AJ Boydston
Source: Angew. Chem. Int. Ed. 2012, 51, 4288.
Keywords: iminium, sigmatropic rearrangement


Problem 6. Provide a mechanism for the following transformation
Contributor: G Lalic
Source: Organometallics. 2002, 21, 3845.
Keywords: metal vinylidene


Problem 5. Provide a mechanism for the following transformation
Contributor: G Lalic
Source: Angew. Chem. Int. Ed. 2011, 50, 5892.
Keywords: Prins, oxonium


Problem 4. Provide a mechanism for the following transformation
Contributor: G Lalic
Source: Chem. Rev. 2004, 104, 2401.
Keywords: Pummerer rearrangement, oxonium


Problem 3. Provide a mechanism for the following transformation
Contributor: AJ Boydston
Source: Tetrahedron Lett. 1993, 34, 439.
Keywords: electrophilic aromatic substitution, racemization


Problem 2. Provide a mechanism for the following transformation
Contributor: AJ Boydston
Source: Org. Lett. J. Org. Chem. 1989, 54, 4298.
Keywords: enamine, 1,4-addition, retro manich


Problem 1. Provide a mechanism for the following transformation
Contributor: AJ Boydston
Source: Synlett 1996, 521.
Keywords: Horner–Wadsworth–Emmons, diazo