Synthesis of alkaloids from amino acids via N-acyliminium ions generated by one-pot radical decarboxylation–oxidation
作者:Alicia Boto、Rosendo Hernández、Ernesto Suárez
DOI:10.1016/s0040-4039(00)00306-3
日期:2000.4
A one-pot methodology for the synthesis of α-substituted nitrogen heterocycles from commercial amino acids has been developed. Good stereoselectivity can be achieved with chiral substituted rings. This procedure has been applied to the synthesis of piperidine, pyrrolidine and indolizidinone alkaloids.
Eco-friendly N-acyliminium ion chemistry: solvent-free HNTf2 and TIPSOTf-catalyzed α-amidoalkylation of silicon-based π-nucleophiles
作者:Marie-José Tranchant、Charlotte Moine、Raja Ben Othman、Till Bousquet、Mohamed Othman、Vincent Dalla
DOI:10.1016/j.tetlet.2006.04.090
日期:2006.6
The alpha-amidoalkylation of silicon-based pi-nucleophiles is efficiently catalyzed by HNTf2 or TIPSOTf at very low levels of loading in neat conditions. (c) 2006 Elsevier Ltd. All rights reserved.
Diastereoselection of the addition of silyloxyfurans to five-, six- and seven-membered N-acyliminium ions
作者:Maria da Conceição F de Oliveira、Leonardo Silva Santos、Ronaldo Aloise Pilli
DOI:10.1016/s0040-4039(01)01388-0
日期:2001.10
The addition of silyloxyfuran 1a to five-, six- and seven-membered N-acyliminium ions 2 afforded threo-3 as the major isomers (the structures of 3a, 3g and 3m were determined by X-ray analysis). The diastereoisomeric ratio increased with bulkier carbamate groups (Boc>Cbz>CO2Me) with the five- and seven-membered N-acyliminium ions more selective than the six-membered ones. However. erythro-4 isomers predominated when 5-methylsilyloxyfuran 1b was employed (the structures were determined by NOE studies on the corresponding bicyclic lactams 6a.b and 7a,b) and the formation or regioisomer 5 was observed for N-acyliminium ions with Boc (seven-membered series) and Cbz (six- and seven-membered series) groups. (C) 2001 Elsevier Science Ltd. All rights reserved.