Homoallylic ketones and pyrroles by way of copper-catalyzed cascade additions of alkylsubstituted vinyl Grignard reagents to esters

Exploring the scope of the copper-catalyzed cascade addition of vinyl Grignard reagents to carboxylic esters, a set of substituted homoallylic ketones (gamma,delta-unsaturated ketones) have been synthesized in 11%-94% yields from treatment of methyl 4-methoxybenzoate and methyl N-Boc-beta-alaninate with different methyl-, dimethyl-, and phenyl-substituted vinyl Grignard reagents in the presence of catalytic amounts of CuCN in THE The respective 2,4-di-, 2,3,5tri-, and 2,3,4,5-tetrasubstituted pyrroles were obtained in 47%-93% yields from the homoallylic ketones by a sequence featuring ozonolysis followed by Paal-Knorr condensation with ammonium formate.