Silylation of allylic acetates (1) using organodisilanes (2) was carried out in the presence of a catalytic amount of Pd(DBA)2−LiCl at 100 °C. The silylation proceeded smoothly without β-hydrogen elimination of a resulting (π-allyl)palladium intermediate. The added chloride salt such as LiCl or NaCl was indispensable for the catalytic activity. On the other hand, remarkable improvement of the silylation was realized by employing allylic trifluoroacetates (4) in place of the acetates (1) as the substrates. The silylation proceeded even at room temperature, and the added chloride salts was not necessary as the catalyst component. In the silylation, transmetalation of the disilanes (2) with (η3-allyl)palladium intermediate (7) might be a critical step in the catalytic cycle. Model reactions for the transmetalation were carried out.

No abstract

Silylation of Allylic Trifluoroacetates and Acetates Using Organodisilanes Catalyzed by Palladium Complex.-It is found that in the presence of Pd(dba)2/LiCl allylic acetates like (I) and (V) undergo efficient silylation with organodisilanes such as (II) at 100 • C. Under these conditions the undesired . beta.-hydrogen elimination process is not observed. Starting from allylic trifluoroacetates like (VI), (VII), and (X) the silylation proceeds more efficiently even at room temperature, and the added chloride salt is not necessary for successful reaction. -(TSUJI, Y.; FUNATO, M.; OZAWA, M.; OGIYAMA, H.; KAJITA, S.; KAWAMURA, T.; J.

1993organo-silicon compounds, acyclic C derivatives organo-silicon compounds, acyclic C derivatives S 0062 -217Palladium-Catalyzed Silylation of Allylic Acetates with Hexamethyldisilane or (Trimethylsilyl)tributylstannane.-The first general method for the silylation of allylic acetates such as (I) or (IV) with hexamethyldisilane (II) is achieved in the presence of Pd(dba)2 at 100 • C. Furthermore, (trimethylsilyl) tributylstannane (VIII) is found to be a reactive silylating reagent even at room temperature. -(TSUJI, Y.; KAJITA, S.; ISOBE, S.; FUNATO, M.; J.