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
BF<sub>3</sub>·OEt<sub>2</sub> catalyzed decarbonylative arylation/C–H functionalization of diazoamides with arylaldehydes: synthesis of substituted 3-aryloxindoles
作者:Sengodagounder Muthusamy、Ammasi Prabu
DOI:10.1039/d2ob00003b
日期:——
A metal-free BF3·OEt2 catalyzed direct decarbonylative arylation of diazoamides with readily accessible aryl aldehydesunder an open-air atmosphere was developed to afford 3-aryloxindoles via 1,2-aryl migration with high selectivity. The reaction offers an efficient pathway for 3-arylation of diazoamides under relatively mildconditions, which shows a high level of functional group tolerance of both
A catalyst generated from Pd(dba)(2) and the bulky electron-rich phosphine ligand 2-(dicyclohexylphosphino)-2',4', 6'-tri-i-propyl-1 - 1'-biphenyl is effective for the alpha-arylation of oxindoles. Generation of the potassium-enolates of a range of oxindoles allows coupling with aryl chlorides, bromides, and triflates. Significant variation of the substitution pattern on both the oxindole and aryl halide is possible.