Palladium(II)-assisted dialkylation and alkylation/acylation of optically active ene carbamates via trialkylorganostannane cross-coupling and carbonylative coupling processes
作者:John J. Masters、Louis S. Hegedus、Joaquin Tamariz
DOI:10.1021/jo00019a038
日期:1991.9
Alkylation of benzyl vinyl carbamate and propene with the anions of diethyl methylmalonate or dimethyl malonate in the presence of palladium (II) chloride, followed by cross-coupling or carbonylative cross-coupling with organostannanes, effected an overall dialkylation or alkylation/acylation of the monoolefin substrate. Complete control of stereochemistry in this palladium(II)-assisted reaction was observed using optically active ene carbamates affording beta-amino-unsaturated keto esters in good chemical yields and excellent optical purity.
CaCl<sub>2</sub>, Bisoxazoline, and Malonate: A Protocol for an Asymmetric Michael Reaction
A mild protocol for the asymmetric Michael addition of dimethyl malonate to various alpha,beta-unsaturated carbonyl compounds was developed. The salient feature of this methodology is that a cheap and environmentally friendly Lewis acid, CaCl2, was used as a catalyst. An aminoindanol- and pyridine-derived ligand provided in the presence of CaCl2 Michael adducts in moderate to high enantioselectivities. The scope of the reaction was demonstrated.