Organic Chemistry Portal
Organic Chemistry Highlights

Monday, March 9, 2015
Douglass F. Taber
University of Delaware

Organic Functional Group Interconversion

Gojko Lalic of the University of Washington developed (Angew. Chem. Int. Ed. 2014, 53, 6473. DOI: 10.1002/anie.201402238) conditions for the preparation of the fluoride 2 by SN2 displacement of the triflate 1. Ross M. Denton of the University of Nottingham showed (Tetrahedron Lett. 2014, 55, 799. DOI: 10.1016/j.tetlet.2013.11.098) that a polymer-bound phosphine oxide activated with oxalyl bromide would convert an alcohol 3 to the bromide 4. The polymer could be filtered off and reactivated directly. Jonas C. Peters and Gregory C. Fu of Caltech devised (J. Am. Chem. Soc. 2014, 136, 2162. DOI: 10.1021/ja4126609) a photochemically-activated Cu catalyst that mediated the displacement of the bromide 5 by the amide 6 to give 7. Mark L. Trudell of the University of New Orleans used (Synthesis 2014, 46, 230. DOI: 10.1055/s-0033-1340142) an Ir catalyst to couple the amide 9 with the alcohol 8, leading to 10.

Tohru Fukuyama of Nagoya University converted (Org. Lett. 2014, 16, 727. DOI: 10.1021/ol403415z) the unsaturated aldehyde 11 into the ester 12. As the transformation proceeded via protonation of the enolized acyl cyanide, the less stable diastereomer was formed kinetically. Brindaban C. Ranu of the Indian Association for the Cultivation of Science developed (Org. Lett. 2014, 16, 1040. DOI: 10.1021/ol500134p) conditions for the coupling of an alkenyl halide 13 with a phenol, leading to the vinyl ether 14. Inter alia, this would be a convenient way to hydrolyze an alkenyl halide to the aldehyde. Vinyl ethers can also be oxidized directly to the ester, and to the unsaturated aldehyde. Pallavi Sharma and John E. Moses of the University of Lincoln observed (Org. Lett. 2014, 16, 2158. DOI: 10.1021/ol500618w) that the cyanation of the alkenyl halide 15 delivered 16, with retention of the geometry of the alkene. Jitendra K. Bera of the Indian Institute of Technology Kanpur uncovered (Tetrahedron Lett. 2014, 55, 1444. DOI: 10.1016/j.tetlet.2014.01.045) "on water" conditions for the hydrolysis of a terminal alkyne 17 to the methyl ketone 18.

Jiannan Xiang and Weimin He of Hunan University prepared (Eur. J. Org. Chem. 2014, 2668. DOI: 10.1002/ejoc.201400066) the keto phosphonate 20 by hydrolysis of the alkynyl phosphonate 19. Ken-ichi Fujita of the National Institute of Advanced Industrial Science and Technology cyclized (Tetrahedron Lett. 2014, 55, 3013. DOI: 10.1016/j.tetlet.2014.03.074) the alkyne 21 with CO2, leading to 22.

Danfeng Huang and Yulai Hu of Northwest Normal University prepared (Synthesis 2014, 46, 320. DOI: 10.1055/s-0033-1340317) the Weinreb amide 24 directly from the carboxylic acid 23, with activation by PCl3. Without racemization, Bhubaneswar Mandal of the Indian Institute of Technology Guwahati coupled (J. Org. Chem. 2014, 79, 5420. DOI: 10.1021/jo500292m) the protected amino acid 25 with the amino ester 26 to give 28, using the readily-prepared activating agent 27.

Renata Marcia de Figueiredo and Jean-Marc Campagne of the Institut Charles Gerhardt Montpellier devised (Angew. Chem. Int. Ed. 2014, 53, 5389. DOI: 10.1002/anie.201402147) a strategy for peptide construction in the opposite direction, coupling the activated urea 29 with 25 to give 28. Kounosuke Oisaki and Motomu Kanai of the University of Tokyo established (Angew. Chem. Int. Ed. 2014, 53, 6501. DOI: 10.1002/anie.201402618) a strategy for the cleavage of a peptide at a serine residue. Oxidation of 30 led to 31 and 32. More complex peptides were also cleaved specifically.

D. F. Taber, Org. Chem. Highlights 2015, March 9.