Unexpected Cycloisomerizations of Nonclassical Carbocation Intermediates in Gold(I)-Catalyzed Homo-Rautenstrauch Cyclizations
摘要:
An unexpected gold(I)-catalyzed homo-Rautenstrauch rearrangement of 1-cyclopropyl propargylic esters to cyclohexenones is disclosed. This rearrangement represents new evidence for the recently discussed gold-stabilized non-classical carbocation character of intermediates in gold catalysis. A mechanistic study proved partial chirality transfer from optically active propargyl acetates.
Preparation of Bicyclic 1,2,4-Trioxanes from γ,δ-Unsaturated Ketones
作者:Armando P. Ramirez、Andrew M. Thomas、K. A. Woerpel
DOI:10.1021/ol8022853
日期:2009.2.5
Treatment of γ,δ-unsaturated ketones with hydrogen peroxide and acid provides a rapid entry into the medicinally important 1,2,4-trioxanestructure. Alkene substitution that stabilizes carbocationic intermediates proved to be important for the success of this transformation.
Synthesis of 2-Alkyl-2-cyclopenten-1-ones. A Versatile Kinetic Alkylation-Ozonolysis Procedure for the Preparation of γ-Ketoaldehydes
作者:Niall W. A. Geraghty、Noreen M. Morris
DOI:10.1055/s-1989-27330
日期:——
A range of 2-alkyl-2-cyclopenten-1-ones including the prostaglandin precursor 2-(6-methoxycarbonylhexyl)-2-cyclopenten-1-one and the jasmonoid precursor 2-[(Z)-2-pentenyl]-2-cyclopenten-1-one, have been prepared by a short synthetic route which begins with 6-methyl-5-hepten-2-one and generates the key 1,4-ketoaldehyde intermediates by a kinetic alkylation-ozonolysis procedure.
Recherches sur la synthese totale des alcaloides appartenant a la serie de la carpaine et de la cassine—II
作者:E. Brown、J. Lavoue、R. Dhal
DOI:10.1016/s0040-4020(01)93317-4
日期:1973.1
The synthesis is described of t-6-propyl-3-piperidinol (dl-pseudo-conhydrine) in 3 steps from 4-4-ethylenedioxy heptanal. This reaction is similar to that recently suggested for the biosynthesis of 2-propylpiperidine (coniine).