摘要：

The reaction of allyl acetates with the sodium salt of dimethyl malonate or methyl benzenesulfonylacetate in the presence of catalytic quantities of tetrakis(triphenylphosphine)palladium is probed. The reactivity of 1-(1′-acetoxyethyl)cycloalkenes tails in the order 5 7 6. The ability to invert the normal reactivity of two leaving groups is illustrated. With a trisubstituted double bond olefin stereochemistry is completely retained, but with disubstituted double bonds substantial loss of olefin stereochemistry occurs. The displacement of the allyl acetates proceeds with complete retention of stereochemistry at the center suffering displacement except for the anion of bis(benzenesulfonyl)methane, in which case a mixture of stereoisomers results. The loss of stereochemistry in the latter case stems from stereorandomization of the starting allyl acetate competing with the displacement. By use of a lactone, in which stereorandomization of the leaving group cannot occur, complete retention of configuration at the center undergoing substitution is restored. The mechanism of the reaction is discussed.

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