Transition‐Metal‐Free Reductive Functionalization of Tertiary Carboxamides and Lactams for α‐Branched Amine Synthesis
作者:Derek Yiren Ong、Dongyang Fan、Darren J. Dixon、Shunsuke Chiba
DOI:10.1002/anie.202004272
日期:2020.7.13
A new method for the synthesis of α‐branched amines by reductive functionalization of tertiary carboxamides and lactams is described. The process relies on the efficient and controlled reduction of tertiary amides by a sodium hydride/sodiumiodide composite, in situ treatment of the resulting anionic hemiaminal with trimethylsilyl chloride and subsequent coupling with nucleophilic reagents including
New protocols for controlled reduction of carboxamides to either alcohols or amines were established using a combination of sodium hydride (NaH) and zinc halides (ZnX2). Use of a different halide on ZnX2 dictates the selectivity, wherein the NaH‐ZnI2 system delivers alcohols and NaH‐ZnCl2 gives amines. Extensive mechanistic studies by experimental and theoretical approaches imply that polymeric zinc
established using sodium hydride (NaH) in the presence of sodium iodide (NaI) under mild reaction conditions. The present protocol with the NaH‐NaI composite allows for reduction of not only aromatic and heteroaromatic but also aliphatic N,N‐dimethylamides with wide substituent compatibility. Retention of α‐chirality in the reduction of α‐enantioriched amides was accomplished. Use of sodium deuteride (NaD)
Divergent synthesis of pyrrole carboxamides from pyrrole carboxaldehyde and formamides/amines <i>via</i> oxidative amidation involving pyrrole acyl radicals
作者:Joydev K. Laha、Surabhi Panday、J. Patrick Weber、Martin Breugst
DOI:10.1039/d3cc02766j
日期:——
A non-traditional approach for the synthesis of pyrrole carboxamides frompyrrole carboxaldehyde and formamides or amines with catalytic amounts of nBu4NI and TBHP as oxidants is reported herein. The method is operationally simple providing straightforward access to primary, secondary, and tertiary pyrrole carboxamides in good to excellent yields utilizing inexpensive reagents under mild conditions
本文报道了一种由吡咯甲醛和甲酰胺或胺以催化量的n Bu 4 NI和TBHP作为氧化剂合成吡咯甲酰胺的非传统方法。该方法操作简单,可在温和条件下利用廉价试剂以良好至优异的产率直接获得伯、仲和叔吡咯甲酰胺。与涉及离子反应的传统酰胺化不同,我们当前方法的机理研究揭示了 2- 或 3-吡咯酰基自由基的参与,否则很少假设。本方法的适用性在类药物化合物,即光学纯的碳依托咪酯酰胺的合成中得到进一步证明。