Activated alkyl- and allyl-alkali metal reagents: Contrasting behaviour towards ethylene
作者:Constantinos G. Screttas、Barry R. Steele
DOI:10.1016/0022-328x(93)83106-6
日期:1993.7
regioselectivity of the reaction of metallated hex-1-ene and (+)-α-pinene with CO2 could be substantially modified by the addition of Mg(OCH2CH2OEt)2. Addition of the latter also solubilizes the organometallic reagents. The allylmetallic products from the metallation of hex-1-ene and α-pinene added to ethylene under mild conditions. Whereas up to four molecules of ethylene added to metallated hex-1-ene, only one
乙烯,己烯-1-己烯和(+)-α- pine烯很容易在甲基环己烷中以n BuLi / LiK(OCH 2 CH 2 NMe 2)2系统金属化。通过添加Mg(OCH 2 CH 2 OEt)2可以大大改变金属化的1-己烯和(+)-α-pine烯与CO 2的反应的区域选择性。。后者的添加也溶解了有机金属试剂。在温和条件下,将己烯-1-烯和α-pine烯金属化的烯丙基金属产物添加到乙烯中。尽管最多有四个乙烯分子被添加到金属化的1--1-烯中,但是根据反应物的比例,只有一个或两个被添加到金属化的α-pine烯中。涉及使用多种其他强碱(例如n BuLi / t C 5 H 11 OK和n BuM(M(Li,Na,K),添加和不添加TMEDA)的类似反应表明存在叔胺,除了有助于金属化反应外,对于添加的发生是必不可少的。
Preparation of optically active cyclohexenones: Chirons for the lipophilic moiety of flowery- and woody-like odorant ketones
Opticallyactive 2,5,6,6- and 2,4,4,5-tetraalkylcyclohex-2-en-1-ones ((+)-2a–d and (−)-5a–d), important building blocks for flowery- and woody-likeodorants, have been prepared. Compounds (+)-2a–d and (−)-5a–d were obtained by ozonolysis of the corresponding cyclopentenic precursors, followed by intramolecular aldol condensation. Alternatively, enones (+)-2a–d were reduced to the corresponding allylic