144732-83-2Relevant articles and documents
Applications of crotyldiisopinocampheylboranes in synthesis: A formal total synthesis of (+)-calyculin A
Anderson, Oren P.,Barrett, Anthony G.M.,Edmunds, Jeremy J.,Hachiya, Shun-Ichiro,Hendrix, James A.,Horita, Kiyoshi,Malecha, James W.,Parkinson, Christopher J.,Vansickle, Andrew
, p. 1562 - 1592 (2007/10/03)
The formal total synthesis of the marine metabolite (+)-calyculin A is reported. The key steps involve (i) the use of Brown allylboration chemistry to control the relative and absolute stereochemistry of homoallylic alcohol arrays, thus setting eight of the desired stereocenters; (ii) Stille coupling methodology in the construction of the cyano tetraene unit of the natural product; and (iii) a modified Cornforth-Meyers approach to the synthesis of the oxazole fragment.
The chemistry of cyclic vinyl ethers. 6. Total synthesis of polyether ionophore antibiotics of the calcimycin (A-23187) class
Boeckman Jr., Robert K.,Charette, André B.,Asberom, Theodros,Johnston, Brian H.
, p. 5337 - 5353 (2007/10/02)
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 α-lithio anion) and bromide 49. Subsequent acid-promoted cyclization directly produces the spirocyclic ring system found in the ionophore X-14885A (3). Alternatively, cyclopropanation of substituted vinyl ether 55 followed by acid treatment afforded the spiroketal 58 that was subsequently converted into the polyether ionophore Calcimycin (1) and also Cezomycin (2).
