Patent ID: 8492539

Claim:
A compound of the following general formula, 49B: wherein R 2 is independently hydrogen, a (C 1 -C 6 ) alkyl, hydroxymethyl, methoxymethyl, halomethyl, vinyl, halovinyl, ethynyl, haloethynyl, allyl, or haloallyl; R 3 is independently a (C 1 -C 6 ) alkyl, hydroxymethyl, methoxymethyl, halomethyl, vinyl, halovinyl, ethynyl, haloethynyl, allyl, or haloallyl; R 5 , R 6 are independently H, methyl, benzyl, trityl, triethylsilyl, t-butyldimethylsilyl, t-butyldiphenylsilyl, ethoxymethyl, methoxymethyl (MOM), methoxyethyl (MEM), benzyloxymethyl (BOM), acetyl, benzoyl, pivaloyl, 2-, 3-, or 4-nitrobenzoyl, 2-, 3-, or 4-chlorobenzoyl, or toluoyl; and Nu is F, Cl, N 3 , CN, NO 2 , CF 3 , SCN, OR or NR 2, wherein R is independently selected from the group consisting of arylalkyl, a (C 1 -C 6 ) alkyl, and CH 2 R′, wherein R′ is hydrogen or a (C 1 -C 6 ) alkyl.