We report a dual function asymmetric catalysis by a chiral phosphoric acid catalyst that controls both enantioselective addition of an achiral α‐vinyl allylboronate to aldehydes and pseudo‐axial orientation of the α‐vinyl group in the transition state. The reaction produces dienyl homoallylic alcohols with high Z ‐selectivities and enantioselectivities. Computational studies revealed that minimization
Herein, we successfully achieve this goal by employing a recyclable solid acid/ionicliquidcatalyst system. The dehydration of alkyl- and cycloalkyl-derived diols in an Amberlyst-15/[Emim]Cl system afforded the corresponding 1,3-dienes in good yields, while a Nafion/[Emim]Cl system was demonstrated to be a better catalyst system for the dehydration of aryl-substituted substrates. Our protocol features
The Catalytic Pinacol Rearrangement of 1,2-Diols Using an Antimony(V) Salt.
作者:Tsunehiro Harada、Teruaki Mukaiyama
DOI:10.1246/cl.1992.81
日期:——
In the presence of a catalytic amount of antimony(V) chloride or antimony(V) salt generated from antimony(V) chloride and silver hexafluoroantimonate, the pinacol rearrangement of several 1,2-diols or their trimethylsilyl ethers proceeds smoothly to give the corresponding ketones in good yields.