444582-56-3Relevant academic research and scientific papers
Synthesis of azetidine and pyrrolidine derivatives through selenium-induced cyclization of secondary homoallylamines - A 77Se NMR study
Pannecoucke, Xavier,Outurquin, Francis,Paulmier, Claude
, p. 995 - 1006 (2007/10/03)
Treatment of α-alkyl and α,α-dialkyl homoallylic amines 1 with PhSeX (X = C1, Br, I), in CH3CN containing sodium carbonate produced mixtures of azetidines 2 and pyrrolidines 3. The cyclization also occurred in the absence of Na2CO3, and the corresponding azetidinium and pyrrolidinium salts 2(HX) and 3(HX) were formed in CDCl3 or CH3CN. The crude reaction mixtures were analysed by 77Se NMR. Each product - 2, 3, 2(HX), and 3(HX) - was characterized by its 77Se chemical shift, and the product ratios were determined for each reaction. The ratios of azetidine 2 to pyrrolidine 3 increased not only according to the steric hindrance around the α-carbon, but also with the nature of the counterion X- (PhSeCl 1, R2 ≠H), produced only the azetidinium salts 2(HI), allowing the isolation of the corresponding azetidines 2, albeit in poor yield. Some reactions were monitored by 77Se NMR at the beginning of the addition-cyclization process. No intermediates were observed when PhSeI was used, but the thermodynamic addition products 5(Br), 5(HBr), and some dibromoselenuranes 8 were detected. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
