Vinylogous Aldol Products from Chiral Crotylsilanes Obtained by Enantioselective Rh(II) and Cu(I) Carbenoid Si-H Insertion

Enantioenriched homoallylic ethers containing a alpha,beta-unsaturated ester (syn-vinylogous aldol products) were directly accessed by Lewis acid catalyzed crotylation utilizing chiral silane 2. The reagents were prepared by enantioselective Si-H Insertion to an alpha-diazovinylacetates using Davies' Rh-2(DOSP)(4) catalyst or chiral Cu(I) Schiff base complex.