One-carbon homologation of unsymmetrical ketones through magnesium β-oxido carbenoid rearrangement and trapping the enolate intermediates with electrophiles
A procedure for one-carbon homologation of unsymmetricalketones, including one-carbon ring-expansion of 2-substituted cyclohexanones, through magnesium β-oxido carbenoid rearrangement as the key reaction is described. Addition of the α-sulfinyl carbanion of 1-chloroethyl p-tolyl sulfoxide to an unsymmetricalketone gave two diastereomers as adducts in good yields. The adducts were treated with a base
We present herein an unprecedented desymmetrization of meso 1,3-diones by enantioselective intermolecular condensation. Under the catalysis by a chiral phosphoric acid, a range of readily available 1,3-diones undergo reaction with hydrazines to produce cyclic and acyclic keto-hydrazones bearing an all-carbon quaternary center in high efficiency and enantioselectivity. These compounds are also highly
bifunctional complex containing both a hydrogen bond donor and a Lewis acidic magnesium center was discovered to be a stereoselective cyanosilylation catalyst for structurally flexible acyclic 1,3-diketones. Stereochemically defined vicinal tertiary and quaternary stereocenters can be obtained and further derived to polyfunctionalized molecules.