Metallations and Reactions with Electrophiles of 4-Isopropyl-5,5-diphenyloxazolidin-2-one (DIOZ) with N-Allyl and N-Propargyl Substituents: Chiral Homoenolate Reagents
(M)-configuration (products 9), and the addition to aldehydes and unsymmetricalketones has taken place preferentially from the Si face. A mechanistic model is proposed that is compatible with the stereochemical outcome (assuming kinetic control and disregarding the presence of Li and Ti species in the reaction mixture; cf.L, M in Fig. 4). Hydrolysis of the enamine derivatives leads to lactols, oxidizable to