[2,2]Paracyclophane-Based N,O-Ligands in Alkenylzinc Additions to Aldehydes
摘要:
[GRAPHICS]The application of planar and central chiral [2,2]paracyclophane-based N,O-ligands in asymmetric alkenylzinc additions to various aldehydes is described, which gives rise to very high ee's especially for difficult substrates. A fine-tuning of the alkenylzinc species by employing different transmetalation reagents is reported, allowing control of the steric bulk of the alkenylzinc species and thus the selectivity of the catalysis.
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