Alkenes as Chelating Groups in Diastereoselective Additions of Organometallics to Ketones

Alkenes have been discovered to be
chelating groups to Zn­(II),
enforcing highly stereoselective additions of organozincs to β,γ-unsaturated
ketones. 1H NMR studies and DFT calculations provide support
for this surprising chelation mode. The results expand the range of
coordinating groups for chelation-controlled carbonyl additions from
heteroatom Lewis bases to simple C–C double bonds, broadening
the 60 year old paradigm.