Hosomi

Conventional synthetic schemes to produce 1,6-disubstituted products, e.g. reaction of a - with d -synthons, are largely unsuccessful. An exception is the following reaction, which provides a useful alternative when Michael type additions fail, e. g., at angular or other tertiary carbon atoms. In such cases the addition of allylsilanes catalyzed by titanium tetrachloride, the Sakurai reaction, is most appropriate (A. Hosomi, 1977). Isomerization of the double bond with bis(benzonitrile-N)dichloropalladium gives the y-double bond in excellent yield. Subsequent ozonolysis provides a pathway to 1,4-dicarbonyl compounds. Thus 1,6-, 1,5- and 1,4-difunctional compounds are accessible by this reaction. 

Reduction of a-trimethylsily1niethylacrylic acid by lithium aluminum hydride prepared according to Hosomi, A. Hashimoto, H. Sakurai, H. Tetrahedron Lett. 1980, 951. Trost, B. M. Curran, 0. P., unpublished results. 

JOC4423 A. Hosomi, S. Hayashi, K. Hoashi, S. Kohra, and Y. Tominaga,... 

Almost 15 years ago Sakurai and Hosomi, in pioneering work, showed that intermolecular addition of an allylsilane to a,j6-unsaturated ketones in the presence of titanium(IV) chloride as the Lewis acid gave the desired 1,4-addition products1 4. In the case of 4,4a,5,6,7,8-hexahy-dro-2(3//)-naphthalenone, reaction was shown to proceed by 1,4-addition with exclusive production of the ris-fused product in high chemical yield. 

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