An Efficient, Overall [4+1] Cycloadditon of 1,3-Dienes and Nitrene Precursors
作者:Qiong Wu、Jian Hu、Xinfeng Ren、Jianrong Steve Zhou
DOI:10.1002/chem.201101630
日期:2011.10.4
Intermolecular cycloadditions of conjugated dienes and nitreneprecursors usually produce aziridines. A generally useful method was lacking to directly provide the [4+1] cycloadducts, 3‐pyrrolines. We have realized this transformation by using an uniquely active catalyst, copper(II) 1,1,1,5,5,5‐hexafluoroacetylacetonate ([Cu(hfacac)2]). The method is applicable to a wide array of dienes with good yields
Efficient synthesis of 3-sulfolenes from allylic alcohols and 1,3-dienes enabled by sodium metabisulfite as a sulfur dioxide equivalent
作者:Hang T. Dang、Vu T. Nguyen、Viet D. Nguyen、Hadi D. Arman、Oleg V. Larionov
DOI:10.1039/c8ob00745d
日期:——
We present herein an efficient and practical method for a gram scale synthesis of 3-sulfolenes using sodium metabisulfite as a safe, inexpensive, and easy to handle sulfur dioxide equivalent. Diversely-substituted 3-sulfolenes can be prepared by reacting a variety of 1,3-dienes or allylicalcohols with sodium metabisulfite in aqueous hexafluoroisopropanol (HFIP) or in aqueous methanol in the presence
Preparation of α,ω-alkanediylbis-(3-sulfolenes) as precursors for α,ω-bis-(1,3-dienyl)alkanes
作者:Ta-shue Chou、Chung-Wen Ko、Teng-Kuei Yang
DOI:10.1016/s0040-4020(01)81995-5
日期:1992.1
The sequential substitution reactions of α,ω-diiodoalkanes with two units of 3-sulfolenyl anions conveniently lead to the formation of α,ω-alkanediylbis-(3-sulfolenes) 7. These bissulfolenes are stable precursors for the corresponding bis-(1,3-dienyl)alkanes 16 and the transformation can be readily achieved by a simple thermolytic cheletropic reaction.
Small-Ring Compounds. XIV. Radioactive Cyclobutanone from Ketene and Diazomethane-<sup>14</sup>C<sup>1</sup>
作者:Dorothy A. Semenow、Eugene F. Cox、John D. Roberts
DOI:10.1021/ja01594a069
日期:1956.7
It has been shown by the ^(14)C-tracer technique that cyclobutanone is formed from the reaction OF ketene with diszomethane-^(14)C via an intermediate possessing the symmetry properties of cyclopropanone.
Generation of highly strained 2,3-bridged 2H-azirines via cycloaddition reactions of 2-azidobuta-1,3-dienes and photolysis of the resulting cyclic vinyl azides
and with electron-poor dienophiles to generate the Diels–Alder products 12a,b, 13a,b, 14a,b, 15a,b, and 16b. Both types of reactions provide an access to cyclic vinyl azides, which lead to short-lived 2,3-bridged2H-azirines 18a,b and 20a,b on photolysis. Whereas the highlystrained heterocycle 18b could be characterized by low temperature NMR spectra, the bridgehead azirines 18a and 20a,b were trapped
用二氧化硫处理2-azidobuta-1,3-dienes 10a,b,制备3-azido-3-sulfolenes 11a,b,并用贫电子的亲二烯体生成Diels–Alder产品12a,b,13a,b,14a,b,15a,b和16b。两种类型的反应都提供了进入环状乙烯基叠氮化物的途径,这导致了短寿命的2,3-桥连2 H-叠氮基18a,b和20a,b光解。高应变的杂环18b可以通过低温NMR光谱表征,而桥头基叠氮基18a和20a,b被环戊二烯通过立体选择性[4 + 2]-环加成法或氰化氢捕获而得到双环2-氰基氮丙啶。后者的转化导致化合物22b显示出温度依赖性的1 H NMR光谱,这是因为氮丙啶N原子上的构型快速平衡。然而,高水平的量子化学研究表明,不仅22b的两种反相异构体(内,外),但每个都涉及两个符合标准的人(椅子,船)。