Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
Tributylstibine can mediate the olefination of carbonyl compounds with bromomalonic ester and with dibromomalonic ester. An initial halophilic attack of tributylstibine on the bromine of bromomalonic or dibromomalonic ester forming an ion pair of bromotributylstibonium cation and malonic (A) or bromomalonic ester carbanion (B), respectively, is proposed. These ion pairs react with carbonyl compounds to achieve subsequent olefination. Alternatively, 2 equiv of A collapse, with elimination of malonic ester, to form stiborane D, and the ion pair B reacts with another equivalent of tributylstibine to form stiborane D. This last undergoes a Wittig-type reaction with carbonyl compound to achieve olefination.
Type of Medium: