Convenient Access to 2-Arylpyrroles from 2-Lithio-<i>N</i>,<i>N</i>-dibenzylcyclopropylamine and Nitriles
作者:Jan Szymoniak、Armin de Meijere、Chloé Tanguy、Philippe Bertus、Oleg Larionov
DOI:10.1055/s-2006-950410
日期:2006.9
N,N-Dibenzylaminocyclopropyl ketimines formed as intermediates upon treatment of 2-lithiated N,N-dibenzylcyclopropylamines with nitriles, being donor-acceptor-substituted cyclopropanes, immediately underwent ring-enlarging rearrangement and 1,2-elimination of dibenzylamine to produce 2-substituted pyrroles in good yields (14 examples, 55-80%).
An atom-economical phosphane-free palladium-catalyzed direct C-2 arylation of unactivated free NH-pyrroles is devised. This method provides a straithforward route to a wide variety of substituted 2-aryl-1H-pyrroles from readily accessible starting materials. Iodoarenes bearing electron-withdrawing and electron-donating substituents are tolerated under the presented reaction conditions. The scope of
5-Arylpyrrole-2-carboxylic acids are important keyintermediates in the synthesis of HIV-1 entry inhibitors (such as NBD-11021 and NBD-14010). Here we present a general method for the synthesis of some 5-arylpyrrole-2-carboxylic acids in three steps starting from pyrrole. By this method, the compounds could be prepared on gram scale and without chromatographic purification. 5-Arylpyrrole-2-carboxylic acids are important
Hydrogenative Dearomatization of Pyridine and an Asymmetric Aza‐Friedel–Crafts Alkylation Sequence
作者:Shuo‐Guo Wang、Shu‐Li You
DOI:10.1002/anie.201309876
日期:2014.2.17
Highly efficient synthesis of enantiomerically enriched substitutedpiperidines has been realized via chiral phosphoric acid catalyzed cascade hydrogenative dearomatization of substituted pyridines and aza‐Friedel‐Crafts reaction in good to excellent yields and enantioselectivity.
stereoselective base-catalyzed (Cs2CO3/DMSO) intramolecular cyclization of the synthesized propargylic derivatives to form (acylmethylidene)pyrrolo[1,2-a]pyrazines of Z-configuration. A concise transition-metal-free strategy for the synthesis of pyrrolo[1,2-a]pyrazines with enone substituents has been developed. It includes the following key steps: (a) cross-coupling of pyrroles with acyl(bromo)acetylenes in solid
摘要 开发了一种简洁的无过渡金属合成具有烯酮取代基的吡咯并[1,2- a ]吡嗪的策略。它包括以下关键步骤:(a)吡咯与固体氧化铝中的酰基(溴)乙炔在室温下交叉偶联,得到2-(酰基乙炔基)吡咯;(b)将炔丙基胺加到上述乙炔中,形成相应的N-炔丙基亚氨基;(c)合成的炔丙基衍生物的化学和立体选择性碱催化的(Cs 2 CO 3 / DMSO)分子内环化反应形成Z-构型的(酰基亚甲基)吡咯并[1,2- a ]吡嗪。 开发了一种简洁的无过渡金属合成具有烯酮取代基的吡咯并[1,2- a ]吡嗪的策略。它包括以下关键步骤:(a)吡咯与固体氧化铝中的酰基(溴)乙炔在室温下交叉偶联,得到2-(酰基乙炔基)吡咯;(b)将炔丙基胺加到上述乙炔中,形成相应的N-炔丙基亚氨基;(c)合成的炔丙基衍生物的化学和立体选择性碱催化的(Cs 2 CO 3 / DMSO)分子内环化反应形成Z-构型的(酰基亚甲基)吡咯并[1