THE FIRST TOTAL SYNTHESIS OF (-)-BENZOMALVIN A AND BENZOMALVIN B VIA THE INTRAMOLECULAR AZA-WITTIG REACTIONS

The first total synthesis of(-)-benzomalvin A, which possesses 4(3H)-q uinazolinone and 1,4-benzodiazepin-5-one moieties, was described. Both of 6- and 7-membered ring skeletons were efficiently constructed by t he intramolecular aza-Wittig reactions as the key reactions. The enant iomeric excess of synthetic (-)-benzomalvin A was more than 99.7 % bas ed on HPLC analysis using specially modified cellulose as a stationary phase. Furthermore, investigation on a specific conformational dynami c behavior of(-)-benzomalvin A was carried out by NMR studies and X-ra y crystallographic analysis, and benzomalvin B was readily synthesized from (-)-benzomalvin A by only two steps. (C) 1998 Elsevier Science L td. All rights reserved.