Deng Kai, Bensari Ahlem, Cohen Theodore
Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
J Am Chem Soc. 2002 Oct 16;124(41):12106-7. doi: 10.1021/ja027988c.
The versatility of intramolecular carbolithiation of simple alkenes to yield cyclopentylmethyllithiums by unconjugated organolithiums is greatly increased (1) by generating the organolithiums by reductive lithiation of phenyl thioethers with aromatic radical anions and (2) by using allylic or homoallylic alcohol groups on the receiving alkene. This type of reductive lithiation allows virtually any kind of organolithium to be generated, usually in a connective manner. Furthermore, the allylic or homoallylic lithium oxyanionic groups on the alkene greatly accelerate the reactions and lead in most cases to completely stereoselective cyclization at -78 degrees . Most significantly, the trans stereoselectivity is the opposite from that observed when the organometallic is allylic. A four-membered ring has also been generated by this method.
（1）通过用芳族自由基阴离子对苯基硫醚进行还原锂化来生成有机锂；（2）在接受烯烃上使用烯丙基或高烯丙基醇基团。这种类型的还原锂化几乎可以生成任何种类的有机锂，通常是以一种连贯的方式。此外，烯烃上的烯丙基或高烯丙基锂氧基阴离子基团极大地加速了反应，并且在大多数情况下在-78℃导致完全立体选择性环化。最显著的是，反式立体选择性与有机金属为烯丙基时所观察到的相反。通过这种方法也生成了一个四元环。
