Enantioselective Pictet–Spengler reactions of isatins for the synthesis of spiroindolones
摘要:
The condensation cyclization between isatins and 5-methoxy tryptamine catalyzed by chiral phosphoric acids provides spirooxindole tetrahydro-beta-carboline products in excellent yields (up to 99%) and enantioselectivity (up to 98:2 er). A comparison of catalysts provides insight for the substrate scope and factors responsible for efficient catalytic activity and selectivity in the spirocyclization. Chiral phosphoric acids with different 3,3'-substitution on the binaphthyl system and opposite axial chirality afford the spiroindolone product with the same absolute configuration. (C) 2011 Elsevier Ltd. All rights reserved.
Enantioselective Pictet–Spengler reactions of isatins for the synthesis of spiroindolones
作者:Joseph J. Badillo、Abel Silva-García、Benjamin H. Shupe、James C. Fettinger、Annaliese K. Franz
DOI:10.1016/j.tetlet.2011.08.071
日期:2011.10
The condensation cyclization between isatins and 5-methoxy tryptamine catalyzed by chiral phosphoric acids provides spirooxindole tetrahydro-beta-carboline products in excellent yields (up to 99%) and enantioselectivity (up to 98:2 er). A comparison of catalysts provides insight for the substrate scope and factors responsible for efficient catalytic activity and selectivity in the spirocyclization. Chiral phosphoric acids with different 3,3'-substitution on the binaphthyl system and opposite axial chirality afford the spiroindolone product with the same absolute configuration. (C) 2011 Elsevier Ltd. All rights reserved.