Palladium−Iminophosphine-Catalyzed Alkynylstannylation of Alkynes
摘要:
A palladium complex coordinated by an iminophosphine ligand was found to catalyze the addition of alkynylstannanes to a carbon-carbon triple bond of various alkynes in moderate to good yields with exclusive syn selectivity. The alkynyl group in the stannanes was attached: mainly to the internal carbon of terminal alkynes, except for 1-alkyn-3-ones and alkynoates, where the alkynyl group was connected to the terminal carbon. Steric bulk of the ligand markedly influenced on the regioselectivity and reaction rate: an iminophosphine with a bulkier imino moiety accelerated the alkynylstannylation with higher regioselectivity. On the basis of these observations, the. mechanism of the present reaction is discussed.
The palladium–iminophosphine catalyst for the reactions of organostannanes
作者:Eiji Shirakawa、Tamejiro Hiyama
DOI:10.1016/s0022-328x(98)01056-0
日期:1999.3
organostannanes with aryl halides. The mechanistic studies show that the reaction of an alkynylstannane proceeds through an unprecedented catalytic cycle which involves an oxidative addition of the organostannane to the Pd(0)–iminophosphine complex. The catalyst was demonstrated to be also useful for the carbostannylation of alkynes and the homocoupling reaction of organostannanes.
A palladium complex coordinated by an iminophosphine ligand was found to catalyze the addition of alkynylstannanes to a carbon-carbon triple bond of various alkynes in moderate to good yields with exclusive syn selectivity. The alkynyl group in the stannanes was attached: mainly to the internal carbon of terminal alkynes, except for 1-alkyn-3-ones and alkynoates, where the alkynyl group was connected to the terminal carbon. Steric bulk of the ligand markedly influenced on the regioselectivity and reaction rate: an iminophosphine with a bulkier imino moiety accelerated the alkynylstannylation with higher regioselectivity. On the basis of these observations, the. mechanism of the present reaction is discussed.