Synthesis of Isoxazoles via Electrophilic Cyclization
摘要:
A variety of 3,5-disubstituted 4-halo(seleno)isoxazoles are readily prepared in good to excellent yields under mild reaction conditions by the reaction of 2-alkyn-1-one O-methyl oximes with ICI, I-2, Br-2, or PhSeBr.
Synthesis of Isoxazoles via Electrophilic Cyclization
摘要:
A variety of 3,5-disubstituted 4-halo(seleno)isoxazoles are readily prepared in good to excellent yields under mild reaction conditions by the reaction of 2-alkyn-1-one O-methyl oximes with ICI, I-2, Br-2, or PhSeBr.
intermediates generated from electrophilic cyclizations for tandem C–C bond construction is a challenging task but constitutes an excellent tool for constructing complex motifs from simpler substrates. We realize herein such a cyclative annulation of alkynyl-oxime ethers with maleimides for the facile construction of isoxazole-phthalimide hybrid motifs throughPd(II) catalysis. This protocol features excellent
利用亲电环化产生的有机钯中间体进行串联 C-C 键构建是一项具有挑战性的任务,但它是从更简单的底物构建复杂基序的绝佳工具。我们在此实现了炔基肟醚与马来酰亚胺的环化,以便通过 Pd(II) 催化轻松构建异恶唑-邻苯二甲酰亚胺杂化基序。该方案具有出色的 C-H 选择区域选择性、广泛的底物范围、良好的官能团耐受性和可扩展性。必要的 KIE 和标记研究可以深入了解反应机制。
Palladium-Catalyzed Carbohalogenation of Olefins with Alkynyl Oxime Ethers: Rapid Access to Chlorine-Containing Isoxazoles
A palladium-catalyzed carbohalogenation of olefins with alkynyl oxime ethers has been described, which provides efficient and practical access to various chlorine-containing isoxazoles. This method exhibits excellent regioselectivity, good functional group compatibility, and mild reaction conditions. The mechanistic studies suggest that the reaction proceeds via a stabilized π-benzyl palladium intermediate