The syntheses of a series of CpW(CO) 2 (π-γ-lactonyl) complexes bearing a tethered aldehyde are described. These π-allyl complexes are prepared as either syn-or anti-stereoisomers. Treatment of these dicarbonyl complexes with NOBF 4 and NaI in CH 3 CN effects an intramolecular allylation of the tethered aldehyde, yielding bicyclic R-methylene butyrolactones comprising a homoallylic alcohol. Both syn-and anti-isomers of tungsten-π-allyl compounds produce the same R-methylene butyrolactones. The cyclizations proceed with high diastereoselectivities to give only the cis-fused bicyclic γ-lactones. The preference for cis-fused stereoselection can be rationalized based on a tricyclic transition state mechanism.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.