Prochiral dihydrosilanes

Asymmetric Alcoholysis of Dihydrosilanes. Optically active difunctional silanes have been obtained by asymmetric alcoholysis of prochiral dihydrosilanes catalyzed by rhodium complexes (73) (eq. [28]). 

Scheme 12. Rhodium catalyzed reactions of prochiral dihydrosilanes.

Asymmetric Hydrosilylation of Symmetric Ketones and Aldehydes by Prochiral Dihydrosilanes (68, 79, 80)... 

TABLE 4. Asymmetric hydrosilylation of symmetric ketones and aldehydes by prochiral dihydrosilanes (after References 50, 52 and 53)... 

TABLE 5. Asymmetric hydrosilylation of prochiral ketones by a prochiral dihydrosilane (after Reference 50)... 

Results of simple and double asymmetric alcoholysis of prochiral dihydrosilanes catalyzed by the chiral rhodium(I) complex, (DIOP)Rh(S)Cl (6), are also shown in Table 23. Optical yields of the simple asymmetric alcoholysis using the chiral rhodium(I) complex were rather low, while the double asymmetric one provided good results [72]. The mechanism of the asymmetric induction may be closely similar to that of the asymmetric hydrosilylation. 

Asymmetric synthesis at a prochiral silicon center in catalytic asymmetric reactions has been effected in the hydrosiiyiation of ketones with dihydrosilanes using rhodium complexes as catalysts . ... 

If prochiral ketones are hydrosilylated with dihydrosilanes carrying different alkyl groups R ) and the siloxane is treated with a Grignard reagent, optically active silanes are produced (7) ... 

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