Double Michael Addition-Cyclization of 2,3-Allenoates with Dialkylzinc

Significance

α,β-Unsaturated cyclohexenones are important building blocks in organic and medicinal chemistry. The development of an efficient highly regio- and stereoselective double addition-cyclization of two molecules of 2,3-allenoates with dialkylzinc is reported. The corresponding substituted cyclohexenones are obtained in high yields and excellent regio- and stereoselectivities. This work is an interesting example of efficient conjugate addition of organozinc compounds to double bonds.