Sequential Metal-Free Thermal 1,3-Dipolar Cycloaddition of Unactivated Azomethine Ylides
作者:Verónica Selva、Elisabet Selva、Pedro Merino、Carmen Nájera、José M. Sansano
DOI:10.1021/acs.orglett.8b01292
日期:2018.6.15
The thermal 1,3-dipolarcycloaddition of unactivated azomethine ylides derived from allylamine and aromatic or heteroaromatic aldehydes with maleimides and 1,1- and 1,2-bis(phenylsulfonyl)ethylene affords endo-2,5-trans cycloadducts in moderate to good yields. DFT calculations provide evidence that the diastereoselectivity observed depends on the isomerization between S- and W-ylides according to Curtin-Hammett’s
Enantioselective allylation of imines catalyzed by newly developed (−)-β-pinene-based π-allylpalladium catalyst: an efficient synthesis of (R)-α-propylpiperonylamine and (R)-pipecolic acid
作者:Rodney A. Fernandes、Jothi L. Nallasivam
DOI:10.1039/c2ob26188j
日期:——
A newly developed Ï-allylpalladium with a (â)-β-pinene framework and an isobutyl side chain catalyzed the enantioselective allylation of imines in good yields and enantioselectivities (20 examples, up to 98% ee). An efficient enantioselective synthesis of the (R)-α-propyl piperonylamine part of DMP 777, a human leukocyte elastase inhibitor and (R)-pipecolic acid have been achieved as a useful application of this methodology.
Synthetic modifications of bifunctional homoallylamines: Synthesis of 2-arylpiperidines, (<i>R</i>)-anatabine and (<i>R</i>)-anabasine
作者:Jothi L. Nallasivam、Rodney A. Fernandes
DOI:10.1080/00397911.2019.1643890
日期:——
into N-heterocycles. The N-allylation and Ru-catalyzed ring-closing metathesis delivered the bioactive 2-arylpiperidines, Nicotiana tabacum alkaloids (R)-anatabine and (R)-anabasine in three steps. A formal synthesis of (R)-N-methylanatabine and (R)-N-methylanabasine is also completed. Graphical Abstract
Abstract A new efficientsynthesis of racemic anatabine is reported. The title target was obtained in an excellent overall yield of 70%, by a five-step synthesis, using cheap reagents and mild reaction conditions. A new efficientsynthesis of racemic anatabine is reported. The title target was obtained in an excellent overall yield of 70%, by a five-step synthesis, using cheap reagents and mild reaction