A straightforward synthesis of indole and benzofuran derivatives
摘要:
A new methodology for the synthesis of indole and benzofuran derivatives has been devised. The starting materials, ortho-substituted aryl diynes, have been easily converted into new unsaturated bis-indolyl and bis-benzofuran derivatives and into 2-ethynylindole and 2-ethynylbenzofuran. Both these products have been further elaborated into more complex unsaturated indole-benzofuran and bis-benzofuran derivatives. (c) 2007 Elsevier Ltd. All rights reserved.
Modification of the Fritsch–Buttenberg–Wiechell rearrangement: a facile route to unsymmetrical butadiynes
作者:Erin T Chernick、Sara Eisler、Rik R Tykwinski
DOI:10.1016/s0040-4039(01)01901-3
日期:2001.12
echell rearrangement has been used to form unsymmetrically substituted 1,3-butadiynes from 1,1-dibromo-olefin precursors. The reaction proceeds via lithium–halogen exchange, followed by migration of the aryl or alkynyl moiety to provide the butadiyne framework. The facile formation of the dibromo-olefins in three steps from commercially available aryl aldehydes or carboxylic acid chlorides makes this
Chemoselective Cobalt(I)-Catalyzed Cyclotrimerization of (Un)Symmetrical 1,3-Butadiynes for the Synthesis of 1,2,4-Regioisomers
作者:Sebastian M. Weber、Gerhard Hilt
DOI:10.1021/acs.orglett.9b01281
日期:2019.6.7
The cobalt(I)-catalyzed cyclotrimerization of (un)symmetrical 1,4-disubstituted 1,3-butadiynes is presented. In the case of unsymmetrical 1,3-butadiynes, this reaction can generate eight 1,2,4-substituted and four 1,3,5-substituted isomers. A single 1,2,4-substituted isomer was formed in excellent yields (up to 99%) and exclusive regioselectivities (>99:1) when symmetrical or a 1,3-butadiyne with an
Control of the Regioselectivity in Cobalt- versus Ruthenium-Catalyzed Alder-ene Reaction of Unsymmetrical 1,3-Diynes
作者:Sebastian M. Weber、Gerhard Hilt
DOI:10.1021/acs.orglett.6b03729
日期:2017.2.3
The Alder-enereaction of trialkylsilyl-substituted 1,3-butadiynes with terminal alkenes was investigated utilizing a cobalt-based catalyst, and the results were compared with Alder-ene rections catalyzed by the [CpRu(H3CCN)3]PF6 catalyst. Obviously, the two catalysts gave complementary results of yn-dienes differing in the site where the new carbon–carbon bond was formed. Of particular interest are
The [4 + 2] cross-benzannulation of conjugatedenynes and diynes under cobalt-catalysis led to 1,2,3-trisubstituted benzene derivatives in good yields. The reaction proceeds smoothly in absolute regiospecific control when symmetrical diynes are applied. Moreover, the use of unsymmetrical diynes was investigated, resulting in the formation of the unprecedented regioisomers as major products, which is
Cobalt-Catalyzed Regio- and Stereoselective Hydrosilylation of 1,3-Diynes To Access Silyl-Functionalized 1,3-Enynes
作者:Hui Leng Sang、Yongyi Hu、Shaozhong Ge
DOI:10.1021/acs.orglett.9b01836
日期:2019.7.5
A regio- and stereoselective hydrosilylation of 1,3-diynes has been developed relying on catalysts generated from bench-stable Co(acac)2 and dppp ligand. A variety of symmetrical and unsymmetrical 1,3-diynes undergo this transformation, yielding the corresponding silyl-functionalized 1,3-enynes in high yields with excellent regioselectivity. Gram-scale reactions and further transformations of the silyl-containing