A Practical Synthesis of 5-Lipoxygenase Inhibitor MK-0633
作者:Francis Gosselin、Robert A. Britton、Ian W. Davies、Sarah J. Dolman、Danny Gauvreau、R. Scott Hoerrner、Gregory Hughes、Jacob Janey、Stephen Lau、Carmela Molinaro、Christian Nadeau、Paul D. O’Shea、Michael Palucki、Rick Sidler
DOI:10.1021/jo100561u
日期:2010.6.18
Practical, chromatography-free syntheses of 5-lipoxygenase inhibitor MK-0633 p-toluenesullonate (1) are described. The first route used an asymmetric zincate addition to ethyl 2,2,2-trifluoropyruvate followed by 1,3,4-oxadiazole formation and reductive amination as key steps. An improved second route features an inexpensive diastereomeric salt resolution of vinyl hydroxy-acid 22 followed by a robust end-game featuring a through-process hydrazide acylation/1,3,4-oxadiazole ring closure/salt formation sequence to afford MK-0633 p-toluenesulfonate (1).
Highly Enantioselective Alkynylation of Trifluoropyruvate with Alkynylsilanes Catalyzed by the BINAP−Pd Complex: Access to α-Trifluoromethyl-Substituted Tertiary Alcohols
作者:Kohsuke Aikawa、Yu̅ta Hioki、Koichi Mikami
DOI:10.1021/ol102541s
日期:2010.12.17
A highlyenantioselective alkynylation catalyzed by the dicationic (S)-BINAP−Pd complex with a variety of alkynylsilanes and trifluoropyruvate is described. The catalytic reaction is applicable to highlyenantioselective addition of polyyne to trifluoropyruvate to construct α-trifluoromethyl-substituted tertiaryalcohols as enantiomerically enriched forms. The alkynyl products can be converted into