Pyrrolidines bearing a quaternary α-stereogenic center. Part 2: Access to proline chimeras, stereoselective approach and mechanistic aspects
摘要:
The present work describes the access to various proline chimeras bearing a quaternary cx-stereogenic center, via the Duhamel ring contraction of heterocyclic enamines. Attempts to induce diastereoselectivity are reported. The 'chiral enamine' strategy afforded the required aminoaldehydes with diastereomeric ratios as high as 85:15. (C) 2000 Elsevier Science Ltd. All rights reserved.
Pyrrolidines bearing a quaternary α-stereogenic center. Part 2: Access to proline chimeras, stereoselective approach and mechanistic aspects
摘要:
The present work describes the access to various proline chimeras bearing a quaternary cx-stereogenic center, via the Duhamel ring contraction of heterocyclic enamines. Attempts to induce diastereoselectivity are reported. The 'chiral enamine' strategy afforded the required aminoaldehydes with diastereomeric ratios as high as 85:15. (C) 2000 Elsevier Science Ltd. All rights reserved.
C(sp<sup>3</sup>)–H dehydrogenation and C(sp<sup>2</sup>)–H alkoxy carbonylation of inactivated cyclic amines towards functionalized N-heterocycles
作者:Yan He、Fang Wang、Xinying Zhang、Xuesen Fan
DOI:10.1039/c6cc10227a
日期:——
A novel and efficient synthesis of tetrahydropyridine-, dihydropyrrole-, and tetrahydroazepine-3-carboxylates via cascade reactions of cyclic amines with CO and alcohols is presented. To our knowledge, this should be the first example in which functionalized N-heterocycles were prepared through Pd-catalyzed C(sp3)-H dehydrogenation and C(sp2)-H carbonylation of cyclic amines.
The synthesis of indolizidine and quinolizidine ring systems by free radical cyclization of 4-aza-6-methoxycarbonyl-5-hexenyl radicals
作者:Athelstan L.J. Beckwith、Steven W. Westwood
DOI:10.1016/s0040-4020(01)81101-7
日期:1989.1
The formation of bicyclic amines by the intramolecular cyclization of 4-aza-6-methoxycarbonyl-5-hexenyl radicals is described. The direct attachment of a nitrogen atom to the double bond changes the electronic nature of the alkene such that the cyclization is less efficient than the all carbon analogue or the other aza-substituted 5-hexenyl cyclizations.The reaction has been used in a short, convenient