One-pot reactions of bicyclic zinc enolate generated from Ni-catalyzed reductive cyclization to furnish octahydro-4,7-ethanobenzofuran-9-one derivatives

Enolates ambushed - asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles

Metal enolates are useful intermediates and building blocks indispensable in many organic synthetic transformations. Chiral metal enolates obtained by asymmetric conjugate additions of organometallic reagents are structurally complex intermediates that can be employed in many transformations. In this review, we describe this burgeoning field that is reaching maturity after more than 25 years of development. The effort of our group to broaden possibilities to engage metal enolates in reactions with new electrophiles is described. The material is divided according to the organometallic reagent employed in the conjugate addition step, and thus to the particular metal enolate formed. Short information on applications in total synthesis is also given.

Diastereo- and enantioselective rhodium(III)-catalyzed reductive cyclization of cyclohexadienone-containing 1,6-dienes

A diastereo- and enantioselective rhodium(III)-catalyzed reductive cyclization of cyclohexadienone-tethered terminal alkenes and (E)-1,2-disubstituted alkenes (1,6-dienes) is reported, providing cis-bicyclic products bearing three contiguous stereocenters with good yields and high diastereo- and enantioselectivities. The kinetic resolution of the racemic precursor is also achieved with good efficiency. Moreover, a subgram-scale experiment, several transformations of the cyclization product, and one-pot preparation of bridged polycyclic frameworks are presented.