B-(.gamma.-(Trimethylsilyl)propargyl)diisopinocampheylborane: A New, Highly Efficient Reagent for the Enantioselective Propargylboration of Aldehydes. Synthesis of Trimethylsilyl-Substituted and Parent .alpha.-Allenic Alcohols in High Optical Purity
Nonracemic α-Allenyl Carbinols from Asymmetric Propargylation with the 10-Trimethylsilyl-9-borabicyclo[3.3.2]decanes
作者:Eliud Hernandez、John A. Soderquist
DOI:10.1021/ol051886k
日期:2005.11.1
[reaction: see text] The asymmetric propargylboration of aldehydes at -78 degrees C in <3 h with 1 provides silylated alpha-allenyl carbinols 6 (60-87%) in high ee (94% to >98% ee). The reagents 1 are easily prepared in both enantiomeric forms with a simple Grignard procedure and air-stable borinate complexes 2. The ozonolysis of 6 proceeds smoothly through an acylsilane intermediate to give a TMS
B-(.gamma.-(Trimethylsilyl)propargyl)diisopinocampheylborane: A New, Highly Efficient Reagent for the Enantioselective Propargylboration of Aldehydes. Synthesis of Trimethylsilyl-Substituted and Parent .alpha.-Allenic Alcohols in High Optical Purity
作者:Herbert C. Brown、Uday R. Khire、Gowriswari Narla