The Synthesis of Velloziolide via Nicholas Reaction Based γ-Carbonyl Cations
作者:James R. Green、Andy A. Tjeng
DOI:10.1021/jo901471b
日期:2009.10.2
The total synthesis of the 9,11-seco-rosane diterpene velloziolide (1) has been accomplished by employing the Nicholas reaction chemistry of 2a as a gamma-carbonyl cation equivalent. An initial model Study demonstrated the utility of Nicholas reactions of 2 in the generation of 4-arylalkynoate Co(2)(CO)(6) complexes, and in conjunction with Gilman cuprate addition and Johnson-Claisen rearrangement chemistry, the preparation of a 3-methyl-3-vinyl-4-arylalkanoate model for velloziolide. The Nicholas reaction/gamma-carbonyl cation methodology was then employed twice in the total synthesis to incorporate onto 3,4-methylenedioxytoluene the 4-carbon unit that became the gem-dimethyltetralin portion of the velloziolide and, subsequently, to incorporate the gamma-arylalkanoate function of the epsilon-lactone.
US7642235B2
申请人:——
公开号:US7642235B2
公开(公告)日:2010-01-05
Oligosubstituted Pyrroles Directly from Substituted Methyl Isocyanides and Acetylenes
作者:Alexander V. Lygin、Oleg V. Larionov、Vadim S. Korotkov、Armin de Meijere
DOI:10.1002/chem.200801395
日期:2009.1
methyl isocyanides 1 onto the triple bond of electron‐deficient acetylenes 2 represents a direct and convenient approach to oligosubstituted pyrroles 3. The scope and limitations of this reaction (24 examples, 25–97 % yield) are reported along with an optimization of the reaction conditions and a rationalization of the mechanism. In addition, a related newly developed CuI‐mediated synthesis of 2,3‐disubstituted