Chiral acylsilanes in organic synthesis. Part 2. The role of the solvent, the organometallic reagent, and the nature of the substrate for the diastereoselectivity of 1,2-additions to racemic alkoxymethyl-substituted acylsilanes

The role of the solvent, the organometallic reagent, and the nature of the substrate for the diastereoselectivity of 1,2-additions to racemic alkoxymethyl-substituted acylsilanes was investigated with the acylsilanes 1a–d by variation of the reaction parameters. The results obtained in this study support strongly the previously proposed preferred ‘chelate-controlled’ reaction path followed under several reaction conditions: highest stereoselectivities were obtained with the best chelating substrates reacting with the most Lewis-acidic organometallic reagents in the least donating solvents. It is shown that almost complete stereoselectivity can be obtained using optimal reaction conditions