Synthesis of Cadinanolide Type of Tricyclicα-Methylene-γ-lactone Using Intramolecular Cyclization ofα-Trimethylsilylmethyl-α,β-Unsaturated Ester with Cyclic Ketone
Synthesis of Cadinanolide Type of Tricyclicα-Methylene-γ-lactone Using Intramolecular Cyclization ofα-Trimethylsilylmethyl-α,β-Unsaturated Ester with Cyclic Ketone
Synthesis of Cadinanolide Type of Tricyclic<i>α</i>-Methylene-<i>γ</i>-lactone Using Intramolecular Cyclization of<i>α</i>-Trimethylsilylmethyl-<i>α</i>,<i>β</i>-Unsaturated Ester with Cyclic Ketone
作者:Chiaki Kuroda、Kunihito Ito
DOI:10.1246/bcsj.69.2297
日期:1996.8
Fluoride-promoted intramolecular cyclization of ethyl 6-(2-oxocyclohex-1-yl)-2-(trimethylsilylmethyl)hex-2-enoate afforded ethyl 2-(1-hydroxybicyclo[4.4.0]decan-2-yl)acrylate as the major product, together with tricyclic α-methylene-γ-lactone, a model compound of cadinanolides. The former product was also converted to γ-lactone. The cyclization reaction promoted by TiCl4 gave the hydroxy ester and its dehydrated product. Both Lewis acid- and fluoride-promoted cyclizations gave a trans-decaline system mainly. This stereoselectivity is completely different from that of Reformatsky cyclization observed by Dreiding and co-workers.