Synthesis of Enantiomerically Enriched Triarylmethanes by Enantiospecific Suzuki–Miyaura Cross-Coupling Reactions
摘要:
The Suzuki-Miyaura cross-coupling of chiral, enantiomerically enriched dibenzylic boronic esters is described. The reaction proceeds with almost complete retention of stereochemistry, providing access to triaryl-methanes, compounds that have high biological activity and are difficult to prepare in enantiomerically pure form using other methods.
Synthesis of enantiomerically enriched β-amino alcohol derivatives via asymmetric lithiation of O-benzyl carbamates–imine addition using (−)-sparteine complexes
作者:Sonia Arrasate、Esther Lete、Nuria Sotomayor
DOI:10.1016/s0957-4166(02)00078-2
日期:2002.3
The asymmetric lithiation of O-benzyl carbamates–imine addition sequence using sec-butyllithium/(−)-sparteine complexes has been studied. The reactions proceed with high diastereoselectivity, giving the threo β-amino alcohol derivatives with modest to good e.e. The best enantioinduction was obtained with O-benzyl carbamates bearing methoxy substituents on the aromatic ring.
We describe a 1,3-boron shift-type reaction of homoallenylboronates at the center (sp) carbon in allenes to afford 2-boryl-1,3-dienes with a variety of substituents.