Patent ID: 7538220

Claim:
A compound having the formula in racemic form, enantiomerically enriched form or enantiomerically pure form; wherein X is a radical precursor; R 5 is a C 1-10 alkyl group, an alkenyl group, an alkynyl group, or a benzyl group; R 6 is an alkyl group, —Si(R 8 R 9 R 10 ) or —(R 7 )Si(R 8 R 9 R 10 ), wherein R 7 is an alkylene group, an alkenylene group, or an alkynylene group; and R 8 , R 9 and R 10 are independently a C 1-10 alkyl group, a C 2-10 alkenyl group, a C 2-10 alkynyl group, an aryl group or a —(CH 2 ) N R 11 group, wherein N is an integer within the range of 1 through 10 and R 11 is a hydroxy group, an alkoxy group, an amino group, an alkylamino group, a dialkylamino group, a halogen atom, a cyano group, —SR c or a nitro group; and R 13 is H, F or —CH 3 .