Process for preparing inhibitors of 3-hydroxy-3-methylglutaryl coenzyme a reductase via a chiral synthon

A process for preparing the compound of structural formula:

• ##STR74## wherein:
• R.sup.2 and R.sup.3 are independently chloro or C.sub.1-3 alkyl;
• and
• R.sup.1 is ##STR75## wherein R.sup.6 is hydrogen, fluoro- or chloro, and R.sup.7 and R.sup.8 are independently hydrogen, chloro or C.sub.1-3 alkyl;
• which comprises the steps of:
• (A) treating a compound of structural formula:
• ##STR76## wherein R.sup.4 is C.sub.1-3 alkyl;
• R.sup.5 is benzyl, or 4-methoxybenzyl;
• with sodium amalgam at 20.degree. to 40.degree. C. for 0.25 to 6 hours to produce the compound of formula:
• ##STR77## (B) followed by treatment with hydrogen in the presence of a hydrogenation catalyst to remove the R.sup.5 group followed by treatment with aqueous acetic acid to produce the compound of structure X ##STR78## (C) followed by treatment with an oxidizing agent to produce the compound of formula ##STR79##