Preparation of Polycyclic Systems by Sequential 5-<i>E</i><i>xo</i>-<i>D</i><i>igonal</i> Radical Cyclization, 1,5-Hydrogen Transfer from Silicon, and 5-<i>E</i><i>ndo</i>-<i>T</i><i>rigonal</i> Cyclization
作者:Derrick L. J. Clive、Wen Yang、Aaron C. MacDonald、Zhongren Wang、Michel Cantin
DOI:10.1021/jo001124x
日期:2001.3.1
diagonal cyclization, and the resulting vinyl radical abstracts hydrogen from silicon to afford a silicon-centered radical. This radical closes in a 5-endo trigonal manner to generate radicals of type 4, which are reduced (4 --> 5) by stannane, except when the starting acetylene carries a terminal trimethylstannyl group. In this case, radicals 4 expel trimethylstannyl radical to afford vinyl silanes
作者:Ryan T. Martin、Ludmila P. Camargo、Stephen A. Miller
DOI:10.1039/c3gc42604a
日期:——
Incorporation of the acetal functional group into the main-chain of polylactic acid affords polyesteracetals that degrade readily in seawater.
将缩醛官能团并入聚乳酸主链中,可以得到易于在海水中降解的聚酯缩醛。
Carbonylation of Formaldehyde with Carbon Monoxide over Cation-Exchange Resin Catalysts
作者:Zheng Bao Wang、Takashi Shimada、Hiroyuki Takagi、Cheol-Hee Ahn、Tsuneji Sano、Kazuo Soga、Ikuo Takahashi、Takashi Masuda
DOI:10.1246/bcsj.72.1935
日期:1999.8
The carbonylation of formaldehyde with carbon monoxide was carried out over two kinds of cation-exchange resins as solid acid catalysts. Effects of reaction conditions on the catalytic performance were studied. From 1H NMR, 13C NMR, IR, and GC-MS analyses of the products obtained, it was found that 1,3-dioxolan-4-one (1,3-DOX-4) is selectively produced over the cation-exchange resins. The carbonylation of formaldehyde with carbon monoxide over the cation-exchange resins proceeds under milder reaction conditions, as compared with HZSM-5 zeolite.
Cabonylation of formaldehyde with carbon monoxide has been carried out on HZSM-5 zeolite; from spectroscopic analysis of the products obtained, the formation of 1,3-dioxolan-4-one on the Brønsted acid sites of HZSM-5 zeolite has been demonstrated.
conversion of cyclic ketones to lactones by Oxone in neutral buffered water is extended to heterocyclic ketones, namely, cyclic N-Boc azaketones and oxoethers with the aim of obtaining N-protected azalactones and their analogues with oxygen in place of nitrogen. N-Boc-4-piperidinone and all the cyclic oxoethers were successfully oxidized to lactones, while the azacyclic ketones with nitrogen α-positioned