The chemistry of cyclic vinyl ethers. 6. Total synthesis of polyether ionophore antibiotics of the calcimycin (A-23187) class

RK Boeckman Jr, AB Charette, T Asberom…

Index: Boeckman Jr., Robert K.; Charette, Andre B.; Asberom, Theodros; Johnston, Brian H. Journal of the American Chemical Society, 1991 , vol. 113, # 14 p. 5337 - 5353

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Citation Number: 70

Abstract

Abstract: An extremely convergent (longest linear sequence, 16 steps), fully stereoselective, and potentially general synthesis of the antibiotic ionophores of the Calcimycin (A-23187) class was devised. The key steps involve a coupling reaction between the chiral nonracemic subunits dihydropyran 41 (as the a-lithio anion) and bromide 49. Subsequent acid-promoted cyclization directly produces the spirocyclic ring system found in the ionophore X-14885A ...