A Positional Scanning Approach to the Discovery of Dipeptide-Based Catalysts for the Enantioselective Addition of Vinylzinc Reagents to Aldehydes
作者:Christopher M. Sprout、Meaghan L. Richmond、Christopher T. Seto
DOI:10.1021/jo051342w
日期:2005.9.1
crude form as catalysts for the asymmetric addition of vinylzinc reagents to aldehydes to give chiralallylicalcohols. Three sites of diversity on the ligands were optimized using a positional scanning approach. The optimized structure from the library, ligand 54, was found to catalyze the formation of 10 different (E)-allylicalcohols with enantioselectivities ranging from 90% to 95% ee. This ligand was
Catalytic Enantioselective Synthesis of Secondary Allylic Alcohols from Terminal Alkynes and Aldehydes via 1-Alkenylboron Reagents
作者:Takashi Shono、Toshiro Harada
DOI:10.1021/ol1023213
日期:2010.11.19
enantioenriched secondary allylicalcohols starting from terminal alkynes and aldehydes. Hydroboration of terminal alkynes with dicyclohexylborane and subsequent reaction of the resulting alkenylboron reagents with aldehydes in the presence of a catalytic amount (5 mol %) of 3-(3,5-diphenylphenyl)-H8-BINOL and excess titanium tetraisopropoxide afforded the corresponding allylicalcohols in high enantioselectivities