Claims
- 1. A method of preparing the compound I: ##STR8## wherein Y.sup.1 is O, S or SO.sub.2 and R.sup.1 and R.sup.2 are independently C.sub.1 -C.sub.6 alkyl which comprises:
- (a) stereoselectively reducing a compound of structure 4 to give the lactone 5;
- (b) reacting the lactone 5 with a phenol 9a to give 10;
- (c) hydrolyzing 10 to give the compound I: ##STR9##
- 2. A method according to claim 1, wherein R.sup.1 is methyl, R.sup.2 is n-propyl ,and Y.sup.1 is S.
- 3. A method of claim 1 wherein the reduction of step (a) comprises treating a compound of structure 4 with about 1.1 equivalents of zinc chloride and then with about 2.25 equivalents of DIBAL-H at -80.degree. to -30.degree. C. in a mixture of THF-toluene, followed by pH adjustment and heating to 30.degree.-60.degree. C.
CROSS-REFERENCE
This is a continuation-in-part of U.S. Ser. No. 856,910, filed Apr. 28, 1986, now abandoned.
Foreign Referenced Citations (2)
Number |
Date |
Country |
0104885 |
Apr 1984 |
EPX |
0156233 |
Feb 1985 |
EPX |
Non-Patent Literature Citations (2)
Entry |
R. Frenette et al., J. Org. Chem., 52, 304-307, 1987. |
Ann. Rpts. in Med. Chem., 19, D. M. Bailey ed., 241-251, 1984. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
856910 |
Apr 1986 |
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