Gold catalysis: Alkylideneoxazolines and -oxazoles from intramolecular hydroamination of an alkyne by a trichloroacetimidate
Gold catalysis: Alkylideneoxazolines and -oxazoles from intramolecular hydroamination of an alkyne by a trichloroacetimidate
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DOI：
10.1002/ejoc.200600572
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发表时间：
2006-10-27
影响因子：
2.8
通讯作者：
Frey, Wolfgang
中科院分区：
文献类型：
--
作者：
Hashmi, A. Stephen K.;Rudolph, Matthias;Frey, Wolfgang
合成了几种炔丙基三氯乙酰亚胺酯，并研究了它们与金催化剂的反应。只有与炔丙基和1-甲基炔丙基取代基是一个选择性的环化观察;与氯化金（III）在乙腈中，只有一个快速的氢胺化4-亚甲基-4，5-二氢恶唑的产品得到，在氯仿中的较慢的随后的芳构化不能被阻止，提供恶唑后，长的反应时间。最多可达3333次失误。用金（I）催化剂在氯仿或二氯甲烷中选择性加氢胺化成4-亚甲基-4，5-二氢恶唑，而没有随后的芳构化。金（I）催化剂还允许N-炔丙基甲酰胺化学选择性环异构化为5-亚甲基-4，5-二氢恶唑。((c)Wiley-VCH Verlag GmbH & Co. KGaA，69451魏因海姆，德国，2006）。
Several propargylic trichloroacetimidates have been prepared and their reactions with gold catalysts studied. Only with the propargyl and the 1-methylpropargyl substituent was a selective cyclization observed; with gold(III) chloride in acetonitrile only the product of a fast hydroamination to 4-methylene-4,5-dihydrooxazoles was obtained, in chloroform the slower subsequent aromatization could not be prevented which delivered the oxazoles after long reaction times. Up to 3333 turnovers could be reached. With gold(I) catalysts in chloroform or dichloromethane selective hydroamination to 4-methylene-4,5-dihydrooxazoles without subsequent aromatization was exclusively observed. The gold(l) catalysts also allowed chemoselective cycloisomerization of N-propargylcarboxamides to 5-methylene-4,5-dihydrooxazoles. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006).