Chemical Fixation of Carbon Dioxide Co-Catalyzed by a Combination of Schiff Bases or Phenols and Organic Bases
作者:Yu-Mei Shen、Wei-Liang Duan、Min Shi
DOI:10.1002/ejoc.200400083
日期:2004.7
Binaphthyldiamino, ethyldiamino and cyclohexyldiamino Schiff bases can catalyze the reaction of epoxides with carbon dioxide in the presence of catalytic amounts of various organicbases to give the corresponding cyclic carbonates in high yields. The simplest binaphthyldiamino Schiff base, derived from the reaction of binaphthyldiamine with salicylaldehyde, gave the highest yield of cyclic carbonate
Regio- and stereoselective synthesis of thiazoline derivatives <i>via</i> the thioketene-induced ring expansion of aziridines
作者:Qiuyue Wu、Jiaxi Xu
DOI:10.1039/d1cc06535a
日期:——
Metal-free thioketene-induced ring expansion of aziridines gave 4-alkylthiazolines stereospecifically from 2-alkylaziridines through an intramolecular substitution at the less substituted ring carbon and 5-arylthiazolines stereoselectively from 2-arylaziridines via tandem ring cleavage and formation through intimate ion-pair intermediates after nucleophilic addition of aziridines to thioketenes generated
Enantioselective Synthesis and Stereoselective Ring Opening of<i>N</i>-Acylaziridines
作者:Jennifer Cockrell、Christopher Wilhelmsen、Heather Rubin、Allen Martin、Jeremy B. Morgan
DOI:10.1002/anie.201204224
日期:2012.9.24
Kinetic resolution of N‐acylaziridines by nucleophilic ringopening was achieved with (R)‐BINOL as the chiral modifier under boron‐catalyzed conditions (see scheme; Ar=3,5‐dinitrophenyl). The consumed enantiomer of aziridine can be further converted to an enantioenriched 1,2‐chloroamide with recovery of (R)‐BINOL.
Pyrrolidines from β-Aminoselenides via Radical Cyclization. Diastereoselectivity Control by the N-Substituent
作者:Magnus Besev、Lars Engman
DOI:10.1021/ol005829x
日期:2000.6.1
radicals-were prepared by ring opening of N-allylaziridines with benzeneselenol under acidic conditions or by sodium cyanoborohydride reduction of N-allylimines of alpha-phenylselenenyl ketones. The effect of various N-protective groups (acyl, sulfonyl, or phosphinoyl) on diastereoselectivity in thermally or photochemically initiated 3-aza-5-hexenyl reductive radicalcyclization was studied. Whereas N-unprotected