intermediate, 4-methoxybenzyl 2-bromo-4-methoxyphenyl sulfoxide (6), respectively. It was found that compared with the o-sulfanyl aryl bromides, the sulfinyl group at ortho position accelerated the Sonogashira coupling reaction of aryl bromides. Thus, compound 6 was coupled with 3,4,5-trimethoxyphenyl acetylene, followed by mercury-catalyzed cyclization reaction afford compound 2 in 79% overall yield. Raloxifene
The reaction of o-alkynylarenesulfoxide with iodine was investigated in detail, revealing functionalities of the formation of alpha-diketones with sulfenyl, sulfinyl, and sulfonyl. Additives can change the ratio of products to give medium-to-excellent yields. Results show that water is taken into only sulfonyl compound and that other oxygen atoms constructed in the products are presumably derived from sulfoxide of the starting material and molecular oxygen.
Gold- and Iodine-Mediated Internal Oxygen Transfer of Nitrone- and Sulfoxide-Functionalized Alkynes
作者:Dan Chen、Guoyong Song、Aiqun Jia、Xingwei Li
DOI:10.1021/jo201347r
日期:2011.10.21
Intramolecular oxygen transfer of nitrone- and sulfoxide-alkynes was achieved using a catalytic amount of Au(I) and a stoichiometric amount of iodine. The Au(I)-catalyzed cyclization of a nitrone-terminal alkyne afforded a cyclic iminoester, while cyclization of analogous nitrone-internal alkynes yielded aldehyde enones. The I-2-mediated cyclization of nitrone-alkynes afforded iodinated gamma-lactams and the I-2-mediated internal redox of the closely related sulfoxide alkynes gave diketones functionalized with a thoiether.