Microwave-assisted synthesis of indole-derivatives via cycloisomerization of 2-alkynylanilines in water without added catalysts, acids, or bases
摘要:
An unprecedented green methodology is described for the preparation of differently substituted indoles via microwave-assisted cycloisomerization of 2-alkynylaniline derivatives in water. Moderate to good yields in the cyclization can be achieved for a variety of 2-aminoaryl alkynes. Reactions are run without any added metal catalyst, acid, or base, and do not take place by applying conventional heating. (C) 2009 Elsevier Ltd. All rights reserved.
Diaceno[a,e]pentalenes from Homoannulations of o-Alkynylaryliodides Utilizing a Unique Pd(OAc)2/n-Bu4NOAc Catalytic Combination
摘要:
A heterogeneous catalytic system, Pd(OAc)(2)/n-Bu4NOAc, for the efficient synthesis of diaceno[a,e)pentalenes via a tandem Pd catalytic cycle is reported. The catalytic partner n-Bu4NOAc played indispensable and versatile roles, acting as both the media for recovering active Pd(0) species and their stabilizer. A series of new diaceno[a,dpentalenes were obtained in moderate to high yields, among which the octacydic dianthracenopentalene was found to be highly emissive.
Microwave-assisted synthesis of indole- and azaindole-derivatives in water via cycloisomerization of 2-alkynylanilines and alkynylpyridinamines promoted by amines or catalytic amounts of neutral or basic salts
作者:Adriano Carpita、Arianna Ribecai、Paolo Stabile
DOI:10.1016/j.tet.2010.06.083
日期:2010.8
An efficient methodology is described and exploited for the preparation of differently substituted indoles and azaindoles via microwave-assisted cycloisomerization in water of 2-alkynylanilines and alkynylpyridinamines, which is promoted by catalytic amounts of neutral or basic salts or by stoichiometric weak organic bases. Good to high yields in the cyclization can be achieved for a variety of 2-amino (hetero)aryl alkynes. Reactions are run without any added metal catalyst. A comparison with the cycloisomerization conducted under conventional heating is also described. (C) 2010 Elsevier Ltd. All rights reserved.