Total synthesis of (1RS, 4SR, 5RS)-4-(4,8-dimethyl-5-hydroxy-7-nonenyl)-4-methyl-3,8-dioxabicyclo[3.2.1]octane-1-acetic acid

Claim 1

The process for the preparation of a compound of the formula ##STR21## which comprises reacting a compound of the formula ##STR22## with a compound of the formula LiCH.sub.2 CO.sub.2 C.sub.2 H.sub.5 to form a triene ester of the formula ##STR23## reacting the triene ester with m-chloroperbenzoic acid to form an intermediate of the formula ##STR24## reacting the intermediate first with an aqueous base followed by reaction with acid to form a compound of the formula ##STR25## brominating the compound to form epimeric bromides of the formula ##STR26## treating the mixture of lactones with lithium aluminum hydride to form a mixture of bromo diols of the formula ##STR27## reacting the mixture of bromo diols with sodium hydride to form a mixture of cyclized and uncyclized compounds of the formula ##STR28## reacting the cyclized compound with methanesulfonyl chloride in the presence of a base to form a compound of the formula ##STR29## reacting the product formed with diborane followed by oxidation with hydrogen peroxide to give a primary alcohol of the formula ##STR30## reacting the product with LiCH(CH 3 )CO 2 CH 3 to form a methyl ester of the formula ##STR31## hydrolyzing the ester with base followed by acidification to form an acid of the formula ##STR32## reacting the acid with lithium hydride followed by reaction with 3-methyl-2-butenyl lithium to give a ketone of the formula ##STR33## oxidizing the compound followed by reduction with sodium borohydride, wherein X is chloro or bromo, and Ms is a mesyl group.