Enantioselective Syntheses of Ring-C Precursors of Vit. B12. Reagent Control
摘要:
[GRAPHICS]Enelactones of the general structure S-(-)-I were prepared in three steps from alcohol 21 and acids 22 (ee approximate to 85%). Lactones S-(-)-I are versatile precursors to enelactams II of the type found in Vitamin B-12.
Enantioselective Syntheses of Ring-C Precursors of Vitamin B12. Substrate Control. A Novel Si-Assisted Elimination of Vinyl Bromides
摘要:
[GRAPHICS]Homochiral ring-C precursors 34 of Vitamin B-12 have been prepared by Ireland-Claisen rearrangement of allyl esters 32, followed by a novel Si-assisted elimination of HBr.