58908-07-9Relevant academic research and scientific papers
A highly tunable stereoselective olefination of semistabilized triphenylphosphonium ylides with N -Sulfonyl imines
Dong, De-Jun,Li, Hai-Hua,Tian, Shi-Kai
supporting information; experimental part, p. 5018 - 5020 (2010/06/13)
The Wittig reaction involving direct olefination of triphenylphosphonium ylides (Ph3PCHR) with aldehydes is arguably the most often used method for alkene synthesis, but in general it yields mixtures of Z- and E-alkenes for semistabilized triphenylphosphonium ylides (R = aryl or vinyl). We have developed a simple and efficient protocol to improve the stereoselectivity significantly by replacing the aldehydes used in the Wittig reaction with N-sulfonyl imines, which possess distinct electronic and steric properties relative to aldehydes. A broad range of aromatic, α,β-unsaturated, and aliphatic imines bearing appropriate N-sulfonyl groups smoothly undergo olefination reaction with various benzylidenetriphenylphosphoranes or allylidenetriphenylphosphoranes under mild reaction conditions to afford an array of both Z- and E-isomers of conjugated alkenes in good to excellent yields and with greater than 99:1 stereoselectivity. Moreover, this tunable protocol has been successfully applied to the highly stereoselective synthesis of two anticancer agents, DMU-212 and its Z-isomer.
Chemistry of Oxaziridines. 1. Synthesis and Structure of 2-Arenesulfonyl-3-aryloxaziridines. A New Class of Oxaziridines
Davis, Franklin A.,Lamendola, Joseph,Nadir, Upender,Kluger, Edward W.,Sedergran, Thomas C.,et al.
, p. 2000 - 2005 (2007/10/02)
A new class of oxaziridine derivatives, 2-arenesulfonyl-3-aryloxaziridines (2), is prepared by m-CPBA oxidation of sulfonimines (RSO2N=CHAr).These compounds are the first stable examples of this ring system to have a substituent other than carbon attached to nitrogen and are characterized by a highly electrophilic oxaziridine oxygen atom.These oxaziridines have the E configuration as determined by X-ray crystallography.The presence of the powerful electron-attracting sulfonyl group attached to nitrogen apparently has little effect on the structure of the oxaziridine three-membered ring.Of more significance are the observations that the nitrogen lone pair in 2 is opposite to one of the sulfonyl oxygens and that the long S-N bond length implies little if any conjugative interaction between sulfur and nitrogen.Attempts to prepare oxaziridines via oxidation of sulfonimines, 5, derived from acetophenone gave imidoyl ether 14, a novel Baeyer-Villiger oxidation product of a C-N double bond.
