Isothiourea-catalysed enantioselective Michael addition of N-heterocyclic pronucleophiles to α,β-unsaturated aryl esters
作者:Chang Shu、Honglei Liu、Alexandra M. Z. Slawin、Cameron Carpenter-Warren、Andrew D. Smith
DOI:10.1039/c9sc04303a
日期:——
The isothiourea-catalysed enantioselective Michaeladdition of 3-aryloxindole and 4-substituted-dihydropyrazol-3-one pronucleophiles to α,β-unsaturated p-nitrophenyl esters is reported. This process generates products containing two contiguous stereocentres, one quaternary, in good yields and excellent enantioselectivities (>30 examples, up to > 95 : 5 dr and 99 : 1 er). This protocol harnesses the
An organocatalytic asymmetric sulfenylation of 3-aryloxindoles with N-(sulfanyl)succinimides has been developed by using commercially available (DHQD)2PHAL as catalyst. Various chiral 3-benzylthio-, alkylthio-, and arylthio-substituted oxindoles, containing 3,3-disubstituted quarternary carbon stereocenters, could be obtained in high enantioselectivities (85–97% ee). Furthermore, the opposite enantiomers