Application of 1,2:5,6-di-O-cyclohexylidene-d-mannitol as the chiral director in Matteson’s asymmetric homologation
摘要:
1,2:5,6-Di-O-cyclohexylidene-D-mannitol is the good chiral director in Matteson's asymmetric homologation as indicated by the high enantiomeric excesses (ee's) of the secondary alcohols produced by treatment of the homologation products with alkyllithium or Grignard reagents followed by oxidation. (C) 1999 Elsevier Science S.A. All rights reserved.
A new method for CuF-catalyzed alkenylation and phenylation of aldehydes and an activated ketone using air- and moisture-stable alkenylsilanes and phenylsilane as a nucleophile is described. This methodology was extended to highly enantioselective catalytic alkenylation and phenylation using DTBM-SEGPHOS as a chiral ligand. Substrate generality is broad, and an alkenylsilane with a long alkyl chain
Enantioselective synthesis of sec-allylalcohols by catalytic asymmetric addition of divinylzinc to aldehydes.
作者:Wolfgang Oppolzer、Rumen N. Radinov
DOI:10.1016/s0040-4039(00)80834-5
日期:——
Readily available chiral tridentate ligand catalyzes the highly Si-face selective addition of diethyl-, di-n-propylzinc and, more significantly, of divinylzinc to aromatic and aliphatic aldehydes whereas bidentate ligands and exert a topologically reversed catalytic bias.
Ir(I)-catalyzed decarboxylative allylic amidation of chiral branched benzyl allyl imidodicarboxylates has been shown to proceed with complete retention of enantiomeric purity and configuration. The transformation is stereospecific and appears to be quite general, accommodating a wide range of R groups.
Enantioselective Synthesis of Allylboronates Bearing a Tertiary or Quaternary B-Substituted Stereogenic Carbon by NHC-Cu-Catalyzed Substitution Reactions
作者:Aikomari Guzman-Martinez、Amir H. Hoveyda
DOI:10.1021/ja104254d
日期:2010.8.11
Allylic substitutions that afford alpha-substituted allylboronates bearing B-substituted tertiary or quaternary carbon stereogenic centers are presented. C-B bond-forming reactions, catalyzed by chiral bidentate Cu-NHC complexes, are performed in the presence of commercially available bis(pinacolato)diboron. Transformations proceed in high yield (up to >98%) and site selectivity (>98% S(N)2'), and
Aminocyclopentadienyl Ruthenium Complexes as Racemization Catalysts for Dynamic Kinetic Resolution of Secondary Alcohols at Ambient Temperature
作者:Jun Ho Choi、Yoon Kyung Choi、Yu Hwan Kim、Eun Sil Park、Eun Jung Kim、Mahn-Joo Kim、Jaiwook Park
DOI:10.1021/jo0355799
日期:2004.3.1
tests in the racemization of (S)-4-phenyl-2-butanol showed that 7 is the most active catalyst, although the difference decreased in the DKR. Complex 4 was used in the DKR of various alcohols; at room temperature, not only simple alcohols but also functionalized ones such as allylic alcohols, alkynyl alcohols, diols, hydroxyl esters, and chlorohydrins were successfully transformed to chiral acetates. In