Laboratory of Organic and Medicinal Chemistry (OMC Lab), Department of Chemistry, Malaviya National Institute of Technology Jaipur, Jawaharlal Nehru Marg, 302017, Jaipur, India.
Laboratory of Bioactive Heterocycles and Catalysis (BHC Lab), Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research-Raebareli (Transit Campus), Bijnor-Sisendi Road, Near CRPF Base Camp, Sarojini Nagar, 226002, Lucknow, India.
Chem Asian J. 2022 Aug 15;17(16):e202200398. doi: 10.1002/asia.202200398. Epub 2022 Jun 20.
An unprecedented TMEDA-catalyzed, regioselective, decarboethoxy direct C-N coupling protocol towards the synthesis of dibenzopyrrocolines 17 a-i and 5,6-dihydroindolo[2,1-a]isoquinoline 15 a-f/18 a-c alkaloids via the identification of N,N,N',N'-tetramethylethylenediamine (TMEDA) as a homogeneous catalyst is reported. The transition-metal-free, TMEDA-catalytic novel protocol is operationally simple and showed a wide range of functional group tolerance and substrate compatibility. The gram-scale application and synthesis of naturally occurring Cryptaustoline (dibenzopyrrocoline) alkaloid, further highlights the importance and versatile nature of the developed protocol. This finding also offers a TMEDA-catalyzed direct synthesis of dibenzopyrrocolines and substituted 5,6-dihydroindolo[2,1-a]isoquinoline compounds in a one-pot. The probable reaction pathway involves the free-radical sequential approach via a single electron transfer (SET) mechanism.
本文报道了一种前所未有的 TMEDA 催化的、区域选择性的脱乙氧基直接 C-N 偶联方法，用于合成二苯并吡咯啉 17a-i 和 5,6-二氢吲哚并[2,1-a]异喹啉 15a-f/18a-c 生物碱，通过鉴定 N,N,N',N'-四甲基乙二胺 (TMEDA) 作为均相催化剂。该无过渡金属、TMEDA 催化的新方法操作简单，具有广泛的官能团容忍度和底物相容性。克级应用和天然 Cryptaustoline（二苯并吡咯啉）生物碱的合成进一步突出了所开发方法的重要性和多功能性。这一发现还提供了一种 TMEDA 催化的二苯并吡咯啉和取代的 5,6-二氢吲哚并[2,1-a]异喹啉化合物的一锅法直接合成方法。可能的反应途径涉及通过单电子转移 (SET) 机制的自由基顺序途径。
