The Synthesis of Highly Substituted Isoxazoles by Electrophilic Cyclization: An Efficient Synthesis of Valdecoxib
作者:Jesse P. Waldo、Richard C. Larock
DOI:10.1021/jo701942e
日期:2007.12.1
A large number of functionally substituted 2-alkyn-1-one O-methyl oximes have been cyclized under mild reaction conditions in the presence of ICl to give the corresponding 4-iodoisoxazoles in moderate to excellent yields. The resulting 4-iodoisoxazoles undergo various palladium-catalyzed reactions to yield 3,4,5-trisubstituted isoxazoles, including valdecoxib.
Synthesis of C4-alkynylisoxazoles <i>via</i> a Pd-catalyzed Sonogashira cross-coupling reaction
作者:Wen Yang、Yongqi Yao、Xin Yang、Yingying Deng、Qifu Lin、Dingqiao Yang
DOI:10.1039/c9ra00577c
日期:——
Pd-catalyzed Sonogashira cross-coupling reaction for the synthesis of C4-alkynylisoxazoles from 3,5-disubsitituted-4-iodoisoxazoles and terminal alkynes was described, which could afford the corresponding products with high yield (up to 98%). The results indicated that the steric effect from the group at the C3 position of the isoxazole had greater influence on the cross-coupling reaction than that from
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
Synthesis of Isoxazoles via Electrophilic Cyclization
作者:Jesse P. Waldo、Richard C. Larock
DOI:10.1021/ol052027z
日期:2005.11.1
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.