TBOxCrIIICl-Catalyzed Enantioselective Synthesis of 1,3-Butadien-2-ylcarbinols
摘要:
A highly enantioselective synthesis of 1,3-butadien-2-ylcarbinols is achieved by using the TBOxCr(III)Cl catalyst and homoallenylbromide 1. This method can be further extended to the enantio- and regioselective propargylation of aldehydes.
Asymmetric C(sp)C(sp2) bond formation to give enantiomerically enriched 1,3‐butadienyl‐2‐carbinols occurred through a homoallenylboration reaction between a 2,3‐dienylboronic ester and aldehydes under the catalysis of a chiral phosphoric acid (CPA). A diverse range of enantiomerically enriched butadiene‐substituted secondary alcohols with aryl, heterocyclic, and aliphatic substituents were synthesized
Asymmetric Synthesis of (1,3-Butadien-2-yl)methanols from Aldehydes via [1-(Silylmethyl)allenyl]methanols
作者:María Durán-Galván、Brian T. Connell
DOI:10.1002/ejoc.201000199
日期:2010.5
[1-(Silylmethyl)allenyl]methanols 2 were efficiently synthesized fromaldehydes and (4-bromobut-2-ynyl)trimethylsilane in the presence of a catalytic amount of CrCl 2 and tridentate carbazole ligands. The desired compounds were obtained with good yields (43-88%) and enantioselectivities (55-78 % ee). Alcohols 2 may be treated with TBAF or 2 M HCl in the case of aliphatic substrates, to provide (1,