Stereoselective synthetic approaches to highly substituted cyclopentanes via electrophilic additions to mono-, di-, and trisubstituted cyclopentenes.
Stereoselective synthetic approaches to highly substituted cyclopentanes via electrophilic additions to mono-, di-, and trisubstituted cyclopentenes.
复制标题
通过对单、二和三取代环戊烯进行亲电加成来立体选择性合成高度取代的环戊烷。
DOI：
10.1021/jo000101f
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
Ganem,B
中科院分区：
文献类型：
--
作者：
Clark,MA;Goering,BK;Li,J;Ganem,B
亲电添加到烯代烯烃上具有广泛的合成用途。在这类反应中控制立体选择性引起了相当大的兴趣。然而，烯丙基和均烯丙基取代基在环戊基体系中的作用尚未得到系统的研究。对一系列单取代、二取代和三取代环戊烯的研究报道，其中反式邻位加成有利于亲电试剂对环戊烯体系的非选择性反应。研究了HOBr、HOCl、CH3SCl和四氟硼酸二甲基（甲基硫）磺酸(DMTSF)/ nan3与各种环戊烯底物的加成反应，并考察了各种烯丙基取代基对这些选择性的影响。在高功能化底物上添加HOBr、HOCl和DMTSF可预测地进行同步选择性，主要或只产生一种产物。甲基亚砜酰氯的添加量难以预测，但可以通过适当改变溶剂和底物来调节。结果证明对(+)-trehazolin和(+)-allosamidin的全合成是有用的。
Electrophilic additions to allylically substituted alkenes are of broad synthetic utility. The control of stereoselectivity in such reactions has attracted considerable interest. However, the effect of allylic and homoallylic substituents in cyclopentenyl systems has not been investigated systematically. Studies on a series of mono, di-, and trisubstituted cyclopentenes are reported in whichtrans-vicinal-additions favor asyn-selective approach of electrophiles to the cyclopentene system. The formal addition of HOBr, HOCl, CH3SCl, and dimethyl(methylthio)sulfonium tetrafluoroborate (DMTSF)/NaN3with a variety of cyclopentene substrates has been carried out, and the effects of various allylic substituents on these selectivities have been examined. Additions of HOBr, HOCl, and DMTSF to highly functionalized substrates proceed predictably withsynselectivity, giving predominantly or exclusively one product. Methanesulfenyl chloride additions are less predictable, but can be tuned by suitable alteration of solvent and substrate. Results have proven useful in total syntheses of (+)-trehazolin and (+)-allosamidin.