Organic Chemistry Portal
Organic Chemistry Highlights

Monday, February 12, 2018
Douglass F. Taber
University of Delaware

Enantioselective Synthesis of Alcohols and Amines: The Hayashi Oxylipin Synthesis

Xiu-Qin Dong and Xumu Zhang of Wuhan University developed (Org. Chem. Front. 2017, 4, 555. DOI: 10.1039/C6QO00810K) an Ir catalyst for the enantioselective hydrogenation of an α-hydroxy ketone 1 to the diol 2. Shaolin Zhu of Nanjing University effected (Angew. Chem. Int. Ed. 2017, 56, 2022. DOI: 10.1002/anie.201610990) the selective 1,2-reduction of the enone 3 to the allylic alcohol 4. John F. Hartwig of the University of California, Berkeley and Zhang-Jie Shi of Peking University achieved (Angew. Chem. Int. Ed. 2017, 56, 1092. DOI: 10.1002/anie.201609939) substantial enantioselectivity in the conversion of 5 to 6. Mark McLaughlin and Jongrock Kong of Merck Process reported (Org. Lett. 2017, 19, 926. DOI: 10.1021/acs.orglett.7b00091) the enzymatic hydrolysis of the prochiral 7 to 8.

Erick M. Carreira of ETH Zürich showed (Org. Lett. 2017, 19, 743. DOI: 10.1021/acs.orglett.6b03692) that an α-dichloro aldehyde 9 could be coupled with an alkyne 10 to give the propargylic alcohol 11. Declan G. Gilheany of University College Dublin added (Angew. Chem. Int. Ed. 2017, 56, 4272. DOI: 10.1002/anie.201610462) ethyl magnesium bromide to the alkyl methyl ketone 12 in the presence of a full equivalent of an enantiomerically-pure diaminophenol to give 13 in high ee.

Michael Shipman of the University of Warwick combined (Org. Lett. 2017, 19, 2058. DOI: 10.1021/acs.orglett.7b00653) racemic butadiene monoepoxide (14) with the hydrazine derivative 15 to give 16, that was readily carried on the the diazetidine and then to the diamine (not illustrated). Christopher J. Cordier of Imperial College London rearranged (Chem. Sci. 2017, 8, 4299. DOI: 10.1039/C7SC01042G) the racemic pyridyl ether 17 to the pyridone 18 in high ee. Stefan F. Kirsch of Bergische Universität Wuppertal used (Chem. Commun. 2017, 53, 4513. DOI: 10.1039/C7CC01561E) an organocatalyst to mediate the reduction of 19 to 20. Matthew J. Gaunt of the University of Cambridge oxidized (J. Am. Chem. Soc. 2017, 139, 1412. DOI: 10.1021/jacs.6b12234) 21 to the aziridine 22.

Scott E. Schaus of Boston University assembled (Angew. Chem. Int. Ed. 2017, 56, 1544. DOI: 10.1002/anie.201611332) the amine 26 by adding the allyl boronate 25 to the imine formed from the condensation of aniline 24 with the aldehyde 23. Dieter Enders of RWTH Aachen demonstrated (Chem. Commun. 2017, 53, 6633. DOI: 10.1039/C7CC02874A) that an organocatalyst could mediate the conversion of 27 to the Strecker product 28.

Oxylipins are internal signaling molecules produced by the oxidation of long-chain fatty acids. Masahiko Hayashi of Kobe University established (J. Org. Chem. 2017, 82, 5146. DOI: 10.1021/acs.joc.7b00376) the absolute configuration of one of the oxylipins isolated from the South American shrub Dracontium loretense by preparing its enantiomer 32 from the readily available ester 31. Cu-directed oxidation converted 29 to 30. The derived 31 could readily be brought to high ee by recrystallization.

D. F. Taber, Org. Chem. Highlights 2018, February 12.