Alkynylzirconation of Alkynes and Application to One-Pot Bisalkynylation of Alkynes
摘要:
Stereocontrolled alkynylzirconation of unactivated alkynes was achieved by the reaction of an alkyne with Cp2ZrEt2 and alkynyl halide in this order. After hydrolysis of the alkynylzirconation product, trisubstituted enyne derivatives were obtained in good yields. Functionalized enynes were also prepared by the reaction of the alkynylzirconation products with a variety of electrophiles. Subsequent addition of the second alkynyl halide to the alkynylzirconation products provided an in situ protocol for bisalkynylation of alkynes into (Z)-enediynes in good yields.
Enediynes from Aza-Enediynes: <i>C</i>,<i>N</i>-Dialkynyl Imines Undergo Both Aza-Bergman Rearrangement and Conversion to Enediynes and Fumaronitriles
作者:Liping Feng、Aibin Zhang、Sean M. Kerwin
DOI:10.1021/ol0600638
日期:2006.5.1
[reaction; see text] Aza-enediynes (C,N-dialkynylimines) undergo thermalaza-Bergmanrearrangement to beta-alkynyl acrylonitriles through 2,5-didehydropyridine (2,5-ddp) intermediates. Certain aza-enediynes also undergo an alternative process affording enediynes and fumaronitriles. Studies employing a specifically (l3)C-labeled aza-enediyne show that the conversion to enediyne is second order in aza-enediyne
Reactions of Ph(2)C(3) dianion, prepared from 1,3-diphenylpropyne and n-butyllithium, with dimethyl diselenide and benzylselenocyanate yielded 1,3-bis(methylseleno)-1,3-diphenylpropadiene and 1,3-bis(benzylseleno)-1,3-diphenylpropadiene, respectively, and the reaction with a mixture of dimethyl diselenide and benzylselenocyanate gave 1-benzylseleno-3-methylseleno-1,3-diphenylpropadiene together with
Convenient synthesis of aryl substituted 3-hexene-1,5-diynes
作者:Kakuzo Isagawa、Kazuhiko Mizuno、Tetsuro Majima
DOI:10.1016/s0040-4039(99)01745-1
日期:1999.12
Dimerization of alkynyl carbenes generated from the reaction of 1,1-dibromo-2,3-diarylcyclopropanes (aryl=phenyl, 4-methylphenyl, 4-chlorophenyl) with a strong base under phase-transfer conditions occurs to give E- and Z-1,3,4,6-tetraaryl-3-hexene-1,5-diynes with 1:1 ratio in high yields at ambient temperature. On the other hand, the similar reaction of 1,1-dibromo-2,3-di-(4-methoxy)phenylcyclopropane gave 4,4'-dimethoxychalcone. (C) 1999 Elsevier Science Ltd. All rights reserved.