Patent ID: 7144995

Claim:
A composition having formula (II): wherein R 2 is selected from the group consisting of hydrogen and an acetyl group; R 3 is an alkyl having one to three carbons or allyl; R 4 is selected from the group consisting of hydrogen, a hydroxyl group, a protected hydroxyl group, fluorine, an aminoalkoxy group, an aminoalkoxy group wherein the amino group bears a protecting group, and a methoxy group; R 5 is selected from the group consisting of an alkoxy-N,N-dialkyaminophosphinyl group, a 2-cyanoethoxy-N,N-diisopropylaminophosphinyl group and a methoxy-N,N-diisopropylaminophosphinyl group; and R 6 is a protecting group removable under acidic, neutral, or photochemical conditions.