Reactions of Complex Ligands, LXX. An Intramolecular Alkyne Insertion/Carbonylation/Cyclization Sequence of Chromium Aminocarbene Complexes: A Novel Access to Indole and Indenoindole Skeletons
作者:Thomas Leese、Karl Heinz Dötz
DOI:10.1002/cber.19961290606
日期:1996.6
2-Alkynylanilinocarbene chromium complexes 1–7 bearing a rigid arene C2 spacer between the aminocarbene and alkyne units were prepared from pentacarbonyl(aroyl)chromates(–I), acetyl bromide, and 2-alkynylanilines. They undergo intramolecular cyclization the course of which depends on the substitution pattern at the alkyne terminus. A tandem alkyne insertion into the metal–carbene bond/carbonylation
由五羰基(芳酰基)铬酸盐(-I),乙酰溴和2-炔基苯胺制备在氨基卡宾和炔烃单元之间带有刚性芳烃C 2间隔基的2-炔基丙二烯铬配合物1-7。它们经历分子内环化,其过程取决于炔烃末端的取代方式。一种串列炔插入得到的Cr(CO)的金属-卡宾键/羰基化序列3配位的3-indolylketenes 8,9,12-14,通过使用体积大的取代基; 反应速率随N-烷基化而增加。体积较小的n-炔基壬基碳烯配合物4,5表现出两个竞争的卡宾环化序列:苯并环合导致苯并[ a ]咔唑15、16,而没有事先羰基化的环戊环化提供茚并[1,2- b ]吲哚17、18。
Synthesis of <sup>15</sup>N-labeled heterocycles <i>via</i> the cleavage of C–N bonds of anilines and glycine-<sup>15</sup>N
作者:Jiwen He、Xingguo Zhang、Qiuqin He、Hao Guo、Renhua Fan
DOI:10.1039/d1cc01734a
日期:——
A nitrogen replacement process of anilines by glycine-15N via the cleavage of two C–N bonds for the synthesis of 15N-labeled aromatic heterocycles was reported.
The highly regio- and stereoselective 6-exo-dig mode cyclization of N-acyl-o-alkynylanilines producing 4-alkylidene-3,1-benzoxazines occurred unpredictably by use of a proper catalyst [Pd(OAc)(2)] and an effective additive (acetic acid) under suitable reaction conditions.