Patent ID: 8198444

Claim:
A method for making a compound of formula (III): comprising: (a) allowing a compound of formula (I): to react in the presence of a compound of formula R 1 SR 2 and a chlorine-containing reagent under conditions sufficient to make a compound of formula (II): and (b) allowing the compound of formula (II) to react with a first base and an acylating agent of formula R 4 C(O)OC(O)R 4 or R 4 C(O)X under conditions sufficient to make the compound of formula (III), wherein: R 1 and R 2 are each independently —(C 1 -C 20 )alkyl, —(C 3 -C 8 )cycloalkyl, or -phenyl; R 3 is a protecting group selected from —(C 1 -C 10 )alkyl, -benzyl, —C(O)(C 1 -C 10 )alkyl, —C(O)O(C 1 -C 10 )alkyl, —Si((C 1 -C 10 )alkyl) 3 , —Si(aryl)((C 1 -C 10 )alkyl) 2 , —Si(aryl) 2 ((C 1 -C 10 )alkyl), —P(O)((C 1 -C 10 )alkyl) 2 , —P(S)((C 1 -C 10 )alkyl) 2 , and —S(O)OC 6 H 4 -p-CH 3 ; R 4 is —(C 1 -C 10 )alkyl; and X is —Cl, —Br, or —I.