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  • General, robust, and stereocomplementary preparation of alpha,beta-disubstituted alpha,beta-unsaturated esters.

General, robust, and stereocomplementary preparation of alpha,beta-disubstituted alpha,beta-unsaturated esters.

Organic letters (2009-09-01)
Hidefumi Nakatsuji, Hiroshi Nishikado, Kanako Ueno, Yoo Tanabe
PMID19715286
ABSTRACT

An (E)- and (Z)-stereocomplementary preparative method for alpha,beta-disubstituted alpha,beta-unsaturated esters is performed via three general and robust reaction sequences: (i) Ti-Claisen condensation (formylation) of esters to give alpha-formyl esters (12 examples, 60-99%), (ii) (E)- and (Z)-stereocomplementary enol p-toluenesulfonylation (tosylation) using TsCl-N-methylimidazole (NMI)-Et(3)N and LiOH (24 examples, 82-99%), and (iii) stereoretentive Suzuki-Miyaura cross-coupling (18 examples, 64-96%).