OPENING OF CARBOHYDRATE 5,6-EPOXIDES WITH CHIRAL ACETATE AND PROPIONATE ENOLATE EQUIVALENTS ATTACHED TO THE IRON CHIRAL AUXILIARY [C5H5)FE(CO)(PPH(3))]

The lithium enolate derived from the chiral iron acetyl complex (RS)[( C5H5)Fe(CO)(PPh(3))COCH3] (RS)-1 opens, in the presence of boron trifl uoride etherate, the carbohydrate 5,6-epoxides, 6-anhydro-3-O-benzyl-1 ,2-O-isopropylidene-alpha-D- allofuranose 3, ,6-anhydro-3-O-benzyl-1,2 -O-isopropylidene-beta-L- talonofuranose 4, 6-anhydro-3-O-benzyl-1,2-O -isopropylidene-alpha-D- glucofuranose 5, and 5,6-anhydro-3-O-benzyl- 1,2-O-isopropylidene-beta-L-idofuranose 6 to generate after decomplexa tion the doubly homologated gamma-lactones 3-O-benzyl-6,7-dideoxy- opr opylidene-alpha-D-allo-octafuranuro-5,8-lactone 15, yl-6,7-dideoxy-1,2 -O-isopropylidene-beta-L-talono- octafuranurono-5,8-lactone 16, yl-6,7 -dideoxy-1,2-O-isopropylidene-alpha-D-gluco- octafuranuro 17, and enzy l-6,7-dideoxy-1,2-O-isopropylidene-beta-L-ido- octafuranurono-5,8-lact one 18 respectively. The lithium enolate derived from the homochiral i ron propionyl complexes (R)-[(C5H5)Fe(CO)(PPh(3))COCH2CH3] (R)-2 and ( S)-[(C5H5)Fe(CO)(PPh(3))COCH3] (S)-2 convert after decomplexation 6-an hydro-3-O-benzyl-1,2-O-isopropylidene-alpha-D- glucofuranose 5 to 7(R) -methyl-3-O-benzyl-6,7-dideoxy-1,2-O octafuranurono-5,8-lactone 20 and 7(S)-methyl-3-O-benzyl-6,7-dideoxy-1,2- apylidene-alpha-D-gluco-octaf uranurono-5,8-lactone 22 respectively.