A simple, tandem approach to the construction of pyridine derivatives under metal-free conditions: a one-step synthesis of the monoterpene natural product, (−)-actinidine
followed by concomitant cyclization through an allenylintermediate to afford pyridines in excellent yields, with water as the sole by-product. This mild strategy is also suitable for functionalization of natural products or other advanced intermediates having α,β-unsaturated carbonyl functionality. The utility of the present protocol was showcased with the synthesis of the monoterpene alkaloid, (−)-actinidine
NOVEL METHODS FOR PREPARATION OF SUBSTITUTED PYRIDINES AND RELATED NOVEL COMPOUNDS
申请人:Watkins Edmond Blake
公开号:US20200095245A1
公开(公告)日:2020-03-26
The present invention relates to novel methods of preparation of substituted pyridines and the compounds produced therefrom. In particular, the present invention provides efficient methods for the construction of diversely substituted pyridines, with varying substitution patterns under simple and metal-free conditions with high atom- and pot-economy and excellent functional group tolerance, and which are useful for the synthesis of natural products.
Herein, we report a highly efficient and practical method for pyridine‐derived heterobiaryl synthesis through palladium‐catalyzed electrophilic functionalization of easily available pyridine‐derived quaternary phosphonium salts. The nice generality of this reaction was goes beyond arylation, enabling facile incorporation of diverse carbon‐based fragments, including alkenyl, alkynyl, and also allyl
solvent, an array of xanthenes, thiazole, pyrazine, and pyridazine are compatible with this new arylation approach. The broad substrate scope, mild reaction conditions, and use of water as reaction solvent make this procedure a practical and environmentally friendly method for the synthesis of compounds containing aryl‐heteroaryl motifs.
已经开发出一种高效的可见光促进的N-杂芳烃与芳基重氮盐在水中的“自由基型”偶联。在室温下将反应继续进行的[Ru(联吡啶)3 ]氯2 ⋅ 6 H 2O作为光敏剂,商用灯泡作为光源。在这些反应条件下,吡啶和各种取代的吡啶是有效的底物,仅形成具有不同区域选择性的单取代产物。使用甲酸水溶液作为溶剂,一系列的黄嘌呤,噻唑,吡嗪和哒嗪与这种新的芳基化方法兼容。广泛的底物范围,温和的反应条件以及使用水作为反应溶剂,使得该程序成为合成具有芳基-杂芳基基序的化合物的实用且环境友好的方法。
Synthetic applications of N-N linked heterocycles. Part 7. The preparation of 4-alkyl- and 4-aryl-pyridines by regiospecific attack of Grignard reagents ? to quaternary nitrogen in N-(2,6-dimethyl-4-oxopyridin-1-yl)pyridinium salts
作者:Alan R. Katritzky、Hector Beltrami、Michael P. Sammes
DOI:10.1039/p19800002480
日期:——
N-(2,6-Dimethyl-4-oxopyridin-1-yl)pyridinium salts (4), new reagents for the regiospecific synthesis of 4-substituted pyridines, give moderate to high yields of 4-alkyl- and 4-aryl-pyridines (8)–(10) on reaction with Grignard reagents. The scope and limitations of the reaction, which proceeds via 1,4-dihydro-intermediates (5)–(7), are explored. No 2-substituted pyridines were detected. Some reactions