|Budget Amount *help
¥3,500,000 (Direct Cost : ¥3,500,000)
Fiscal Year 1998 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1997 : ¥2,800,000 (Direct Cost : ¥2,800,000)
This study has been carried out in order to develop novel carbon-carbon and carbon-silicone bond formation reactions possessing high selectivity, efficiency, safety and facilitation through control and utilization of the "specific active chemical species" in electron transfer reactions. Furthermore, some application of these new reactions have been made to bring about asymmetric introduction and development of facile efficient synthesis of new biological active substances, such as cyclopentenones, pyrrolidones and macrocyclic ketones.
It has been found in this study that Mg-promoted electron transfer reaction in DMF I trimethylsilyl chloride (TMSCl), and electroreduction using reactive metal anodes of aromatic alpha, beta-unsaturated systems in the presence of aldehydes, TMSC1, and acid chlorides (or acid anhydrides) brought about efficient and selective reductive cross-coupling reactions to give the corresponding gamma -butyrolactones, beta-silyIated and beta-acylated products in good yields, respectively. At present stage, some diastereoselectivity (40-50%) was observed in the beta-silylation and beta-acylation using chiral alpha, beta-unsaturated amides as the substrates.
Furthermore, it has been also demonstrated that Mg-promoted reductive silylation of aromatic carbonyl compounds led to facile carbon-silicon bond formation to give alpha-trimethylsilylbenzylalcohol derivatives in good yields while the silyl enol ethers were readily obtained from Mg-promoted reductive silylation of aliphatic carbonyl compounds at room temperature. Similar Mg-promoted reductive cross-coupling reaction was found to proceed smoothly through the treatment of aromatic carbonyl compounds with acid anhydrides to yield the corresponding alpha-alkoxybenzyl alkyl ketones efficiently.