Target-oriented synthesis, necessary

Catalytic alcoholysis of silanes by a variety of transition metal based catalysts is a useful method to form silyl ethers under mild conditions (Scheme 19). The process is atom-economical hydrogen gas is the only byproduct. This mild method has not been fully exploited for the preparation of unsymmetrical bis-alkoxysilanes. A catalytic synthesis using silicon alcoholysis would circumvent the need of bases (and the attendant formation of protic byproducts), and eliminate the need for excess silicon dichlorides in the first silyl ether formation. We sought catalytic methods that would ultimately allow formation of chiral tethers that are asymmetric at the silicon center (Scheme 20). Our method, once developed, should be easily transferable for use with high-value synthetic intermediates in a complex target-oriented synthesis therefore, it will be necessary to evaluate the scope and limitation of our new method. 

---