Total synthesis of (+)-blastmycinone, (-)-litsenolide C1, and related natural trisubstituted lactones via alkynyltungsten compounds.

摘要: A general method for total synthesis of natural trisubstituted γ-lactones is developed on the basis chemistry alkynyltungsten compounds. The key step in this approach involves cycloalkenation tungsten−η1-(3R,4S)-pent-1-yne-3,4-diol with aldehydes to give tungsten−oxacarbenium salts, further leading 3-alkylidene-4-hydroxy-5-methyl-γ-lactones upon demetalation. This synthetic sequence proceeds well alkynylaldehydes and MOM derivative tungsten−η1-(3R,4S)-pent-1-yne-3,4-diol. resulting butyrolactone products are transformed into butyrolactones including (+)-blastmycinone, (+)-blastmycinolactol, (+)-antimycinone, NFX-2, (+)-isodihydromahubanolide A. By using same based (R)-ethyl lactate, (−)-litsenolide C1 can be prepared a few steps.