PROCESS FOR THE SYNTHESIS OF DIOXOLANE DERIVATIVES AND THE USE THEREOF IN THE PREPARATION OF DIOXOLANE NUCLEOSIDES WITH amp;beta;-CONFIGURATION

摘要

A process for producing a compound of the formula wherein R1 is a hydroxyl protecting group and L is halogen; by reacting an intermediate of the formula wherein L' is a leaving group; with a Lewis acid of the formula 1356 ו' בתמוז התשס" ג - July 6, 2003 wherein R3', R4' and R5' are independently selected from the group consisting of hydrogen; C1-20 alkyl, optionally substituted by halogens, C6-20 alkoxy or C6-20 aryloxy; C7-20 aralkyl, optionally substituted by halogen, C1-20 alkyl or C1-20 alkoxy; C6-20 aryl, optionally substituted by halogens, C1-20 alkyl or C1-20 alkoxy; trialkylsilyl; fluoro; bromo; chloro and iodo; and R6' is selected from the group consisting of halogen; C1-20 sulphonate esters, optionally substituted by halogens; C1-20 alkyl esters, optionally substituted by halogen; monovalent polyhalides, trisubstituted silyl groups of the general formula (R3') (R4') R5') Si, wherein R3', R4', R5' are as defined above; saturated or unsaturated selenenyl C6-20 aryl; substituted or unsubstituted C6-20 arylsulphenyl; substituted or unsubstituted C1-20 alkoxyalkyl; and trialkylsiloxy.