D. S. Pisoni, D. B. Silva, Rossana A. Schenato
Oct 1, 2004
Citations
0
Influential Citations
4
Citations
Journal
Journal of the Brazilian Chemical Society
Abstract
Este trabalho refere-se a sintese enantiosseletiva da dienona (5R)-4,8-dimethylbicyclo[3.3.0]oct1(8),3-dien-2-one. Este intermediario, pode ser reconhecido como um bloco de construcao versatil para a sintese de uma grande variedade de compostos com esqueleto biciclo[3.3.0]octano. A estrategia sintetica empregada aqui faz uso da reatividade invertida de um precursor cianoidrina TMS-eter, como equivalente de ânion acila, para promover uma reacao de alquilacao intramolecular. A sintese formal do (-)-kelsoeno foi realizada pela preparacao do intermediario avancado (1R,5S,8R)-4,8dimethylbicyclo[3.3.0]oct-3-en-2-one, a partir da hidrogenacao seletiva do composto intitulado (5R)4,8-dimethylbicyclo[3.3.0]oct-1(8),3-dien-2-one. This paper describes the conversion of the readily available (-)-limonene oxide to the new (5R)4,8-dimethylbicyclo[3.3.0]oct-1(8),3-dien-2-one. This compound holds the prospect of serving as a useful chiral building block or intermediate to prepare a variety of compounds having a bicyclo[3.3.0]octane framework. The synthetic strategy made use of the umpolung reactivity of cyanohydrin TMS ether, as an acyl anion equivalent, in order to promote intramolecular alkylation. The formal synthesis of (-)-kelsoene was achieved by preparing a known advanced intermediate (1R,5S,8R)-4,8-dimethylbicyclo[3.3.0]oct-3-en-2-one via selective hydrogenation of the named compound (5R)-4,8-dimethylbicyclo[3.3.0]oct-1(8),3-dien-2-one.