here for the first time are the developments of an efficient method for oxidativecleavage of carbon−carbon double bonds yielding carbonyl compounds by using aryl-λ3-iodanes, which involve a combination of iodosylbenzene and HBF4 in the presence of water. The method serves as a safety alternative to ozonolysis. The oxidativecleavage of olefins probably involves the hitherto unknown direct vicinal dihydroxylations
作者:Yoshifumi Hachisu、Jeffrey W. Bode、Keisuke Suzuki
DOI:10.1002/adsc.200404092
日期:2004.8
The scope and limitations of intramolecular benzoin-forming reactions of aldehydes and ketones catalyzed by the combination of a thiazoliumsalt and a base are described. After optimization of the reaction conditions, five- and six-membered cyclic acyloins were obtained in good to excellent yields and competing reactions such as intramolecular aldol reactions were suppressed. The analogous closure
A novel Pd(II)-catalyzed cascade reaction has been developed that consists of a highly regio- and stereoselective oxa [4 + 2] cycloaddition reaction of o-alkynylbenzaldehydes and an intramolecular carboxylic group quenching of the in situ generated oxonium ion. This new reaction provides a one-step construction of the tetracyclic core structure of chaetophenol C from two simple starting materials.
A novel synthetic approach was developed for the construction of the 1,2,3,4-tetrahydroisoquinoline framework possessing varied functions. The synthetic strategy was based on oxidative ring opening of some indene derivatives through their C=C bond, followed by double reductive amination of the dicarbonyl intermediates with various primary alkyl- or fluoroalkylamines.
Enantioselective formation of quaternary stereocenters using the catalytic intramolecular Stetter reaction
作者:Jennifer L. Moore、Mark S. Kerr、Tomislav Rovis
DOI:10.1016/j.tet.2006.06.042
日期:2006.12
Asymmetric formation of quaternary stereocenters has been accomplished using the catalyticintramolecular Stetter reaction. A variety of tethered aldehydes and Michael acceptors are cyclized in excellent yields and enantioselectivities.