Copper(<scp>i</scp>)-catalysed regio- and diastereoselective intramolecular alkylboration of terminal allenes <i>via</i> allylcopper(<scp>i</scp>) isomerization
作者:Yu Ozawa、Hiroaki Iwamoto、Hajime Ito
DOI:10.1039/c8cc02692k
日期:——
We report the first copper(I)-catalysed intramolecular alkylboration of terminal allenes with an alkyl halide moiety. The reaction provides alkenylboronates bearing a four-membered ring structure with high regio- and diastereocontrol. A possible reaction mechanism is proposed, involving the facile isomerization of an allylcopper(I) intermediate. A DFT study explains the experimental regio- and diastereoselectivity
Unusual regiodivergence in metal-catalysed intramolecular cyclisation of γ-allenols
作者:Jannine L. Arbour、Henry S. Rzepa、Andrew J. P. White、King Kuok (Mimi) Hii
DOI:10.1039/b913295c
日期:——
Different O-heterocycles can be obtained from a common γ-allenol precursor by using Ag, Zn or Sncatalysts; the results were rationalised by molecular modelling.
accelerative asymmetricgoldcatalysis is achieved for the first time via chiral ligand metal cooperation. An asymmetrically positioned remote amide group in the designed chiral binaphthyl-based ligand plays the essential role of a general base catalyst and selectively accelerates the cyclizations of 4-allen-1-ols into one prochiral allene face. The reactions are mostly highly enantioselective with achiral