Asymmetric Deprotonation using <i>s</i>-BuLi or <i>i</i>-PrLi and Chiral Diamines in THF: The Diamine Matters
作者:Giorgio Carbone、Peter O’Brien、Göran Hilmersson
DOI:10.1021/ja107672h
日期:2010.11.3
The solution structures of [(6)Li]-i-PrLi complexed to (-)-sparteine and the (+)-sparteine surrogate in Et(2)O-d(10) and THF-d(8) at -80 °C have been determined using (6)Li and (13)C NMR spectroscopy. In Et(2)O, i-PrLi/(-)-sparteine is a solvent-complexed heterodimer, whereas i-PrLi/(+)-sparteine surrogate is a head-to-tail homodimer. In THF, there was no complexation of (-)-sparteine to i-PrLi until
Catalytic asymmetric deprotonation of a phosphine borane: comparison of two-ligand and one-ligand catalysis
作者:Steven J. Canipa、Peter O’Brien、Sven Taylor
DOI:10.1016/j.tetasy.2009.10.002
日期:2009.10
The catalyticasymmetricdeprotonation of tert-butyldimethylphosphine borane using s-BuLi or n-BuLi and sub-stoichiometric amounts of (−)-sparteine under one-ligand and two-ligand manifolds has been investigated. Using s-BuLi, slightly higher enantioselectivity was obtained using two-ligand catalysis (use of sub-stoichiometric (−)-sparteine in the presence of a stoichiometric amount of a second achiral
Catalytic asymmetric deprotonation of phosphine boranes and sulfides as a route to P-stereogenic compounds
作者:Jonathan J. Gammon、Steven J. Canipa、Peter O’Brien、Brian Kelly、Sven Taylor
DOI:10.1039/b806864j
日期:——
A comparison between phosphine boranes and sulfides in their catalytic asymmetricdeprotonation using organolithiums and sub-stoichiometric amounts of (-)-sparteine has revealed superior catalytic efficiency in the phosphine sulfide deprotonation.