119986-97-9Relevant articles and documents
Studies Directed toward the Total Synthesis of Cerorubenic Acid-III. 1. Expedient Construction of the Tetracyclic Core by Oxyanionic Sigmatropy
Paquette, Leo A.,Poupart, Marc-Andre
, p. 4245 - 4253 (1993)
A synthesis of the ABCD ring framework of cerorubenic acid-III is described.Diketone 5 was first prepared by intramolecular oxidative coupling of the dienolate 10 and then suitably desymmetrized to deliver 15b.Anionic oxy-Cope rearrangement of this intermediate resulted in construction of 18, a ketone not only having all three contiguous stereogenic centers properly established but also equipped with adequate functionality for the further elaboration of ring D.In the present effort, this thrust took the form of homologation to 21, conversion to the activated diene 22, and Diels-Alder cycloaddition to methyl acrylate at high pressure.Once it became obvious that first-formed ketone 26 greatly preferred adoption of trans stereochemistry at the ring juncture, attempts to skirt this issue were made by preparing both 29 and 32.However, these advanced intermediates proved unresponsive to conjugate reduction, and attention was therefore redirected to alternative possible means for elaboration of the eastern sector.
CONFORMATIONAL CONSEQUENCES OF INTRAMOLECULAR CYCLOPROPANATION WITHIN SMALL BICYCLIC SYSTEMS. SYNTHESIS AND DESYMMETRIZATION OF 1-METHYLTRICYCLO2,6>OCTANE-3,5-DIONE
Poupart, Marc-Andre,Paquette, Leo A.
, p. 269 - 272 (2007/10/02)
Diketone 3, available by cyclization of keto acid 2 with PPA/HOAc, undergoes intramolecular oxidative cyclization to 4 by exposure of its dienolate to FeCl3 in DMF at -78 deg C.Convenient monomethylenation of 4 with optical resolution to give optically pu
