[2,3]-Wittig rearrangement of allylic glycolate esters via boron and tin enolates
摘要:
Wittig rearrangement of allylic glycolate esters via boron and tin enolates gave diastereoselectivities as high as 99.5 : 0.5. Tin enolates were more stereoselective than boron enolates.
Diastereoselective construction of cis 2,6-disubstituted tetrahydropyran rings via In(OTf)3-catalyzed intramolecular 2,5-oxonium-ene cyclization: synthetic studies towards the total synthesis of zampanolide and dactylolide
Diastereoselective construction of 2,6-disubstituted tetrahydropyrans with an exocyclic double bond was achieved via the In(OTf)3-catalyzed intramolecular 2,5-oxonium-ene cyclization. Its application was further demonstrated by the synthesis of a common intermediate for both zampanolide and dactylolide, fragment I, with a total yield of 42% in three steps starting from (2E)-3-bromobut-2-enal.