Copper-catalyzed acylation and conjugate addition of zinc homoenolate. Synthesis of 4-and 5-oxo esters

E Nakamura, I Kuwajima

Index: Nakamura,E.; Kuwajima,I. Journal of the American Chemical Society, 1984 , vol. 106, p. 3368

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Citation Number: 119

Abstract

homoenolate and chlorotrimethylsilane (Me3SiC1) from the cyclopropane 1la and ZnC123 followed by successive addition of a catalytic amount (5 mol%) of CuBr-Me2S complex, hexamethylphosphorotriamide (HMPA), and an unsaturated carbonyl compound at 0 OC- room temperature. Nonaqueous workup gives the desired 6-oxo ester as its enol silyl ether with the double-bond specifically (>> 99%) at the mechanistically expected position (eg 1; ...