Process for the preparation of (R)-3-hexyl-5,6-dihydro-4-hydroxy- 6- undecyl-2H-pyran-2-one and (R)-5,6-dihydro-6-undecyl-2H-pyran-2,4(3H)- dione

摘要

A process for the preparation of a tautomeric mixture of compounds of the formulas ##STR1## wherein W is hydrogen or C.sub.6 H.sub. 13, which comprises treating a compound of the formula ##STR2## wherein R is unsubstituted or substituted alkoxy, arylalkoxy, aryloxy or amine and R. sup.1 is hydrogen or when R is alkoxy, substituted alkoxy, substituted amine, unsubstituted or substituted arylalkoxy R.sup.1 can also be metal, with a compound of the formula ##STR3## wherein W is as described above, both X and Y are reducible groups or X is hydrogen and Y is a reducible group or Y is hydrogen and X is a reducible group and, Z is hydroxy or a leaving group to form the compound of formula IV ##STR4## wherein W, X, Y and R are as defined above, the compound of formula IV is treated with a low valent metal to form a tautomeric mixture of compounds of formulas I and Ia, which are useful in the synthesis of tetrahydrolipstatin.