Sc(OTf)3-catalyzed condensation of 2-alkyl-N-tosylaziridine with aldehydes or ketones: an efficient synthesis of 5-alkyl-1,3-oxazolidines
作者:Byungman Kang、Aaron W. Miller、Sandra Goyal、SonBinh T. Nguyen
DOI:10.1039/b902647a
日期:——
Sc(OTf)(3) effectively catalyzes the condensation of 2-alkyl-N-tosylaziridine with a wide variety of aldehydes and ketones, producing 5-alkyl-1,3-oxazolidines in good yields and excellent regioselectivity at catalyst loadings as low as 1 mol%.
Cationic Divalent Metal Sites (M = Mn, Fe, Co) Operating as Both Nitrene-Transfer Agents and Lewis Acids toward Mediating the Synthesis of Three- and Five-Membered<i>N</i>-Heterocycles
practicable yields, involving a single-pot cycloaddition reaction of alkene, nitrene, and ketone (2 + 1 + 2). Mechanistic studies indicate that the most productive bipodal Fe(II) site mediates stepwise addition of nitrene to olefins to generateaziridines with good retention of stereochemistry and further enables aziridine ring opening to unmask a 1,3-zwitterion that can undergo cycloaddition with dipolarophiles
Studies on the Reaction of Aziridines with Nitriles and Carbonyls: Synthesis of Imidazolines and Oxazolidines
作者:Shikha Gandhi、Alakesh Bisai、B. A. Bhanu Prasad、Vinod K. Singh
DOI:10.1021/jo062564c
日期:2007.3.1
presence of molecular sieves. Among various triflates, Zn(OTf)2 has been found to be the best. The cleavage of the N-Ts bond of the cyclized products has been studied in order to make it more versatile in synthesis. The mechanistic aspect of the reaction has been studied by using chiral aziridines as substrates. These formal [3 + 2] cycloaddition reactions of aziridines with nitriles and carbonyls proceed
An efficient iron porphyrin Lewis acid-catalyzed cycloaddition of aziridines with aldehydes has been developed to provide oxazolidines with high regio- and diastereoselectivity. The cycloaddition proceeds in toluene with 1 mol % of the iron catalyst at 25 °C. A theoretical study and synchrotron-based X-ray absorption fine structure measurements provided fundamental insights into the aziridine–iron