Base-induced cyclizations. Reactions of the 1-halo-6-(2-hydroxyethoxy)-cyclohexenes with potassium t-butoxide
作者:A.T. Bottini、F.P. Corson、K.A. Frost、W. Schear
DOI:10.1016/0040-4020(72)88078-5
日期:1972.1
Reactions of 1-bromo-6-(2-hydroxyethoxy)cyclohexene (2) and its chloro analog 3 with potassium t-butoxide in dimethyl sulfoxide at 60–70° gave cyclohex-2-enone ethylene ketal (7) and cis-2,5-dioxabicyclo[4.4.0]dec-7-ene (8) as the major products. Under these conditions, 1-(2-hydroxyethoxy)-1,4-cyclohexadiene (13) is also converted to 7 and elimination products, benzene and ethylene glycol. Conversion
1-溴-6-(2-羟基乙氧基)环己烯(2)及其氯代类似物3与叔丁醇钾在二甲亚砜中在60–70°下反应,得到环己-2-烯酮乙烯缩酮(7)和顺式-2 ,5-二氧杂双环[4.4.0] dec-7-ene(8)为主要产物。在这些条件下,还将1-(2-羟基乙氧基)-1,4-环己二烯(13)转化为7和消除产物苯和乙二醇。通过检查用t-BuOK处理过的7种化合物,可以证明13到7的转化是可逆的。在DMSO- d 6中。在四氢呋喃中2和t-BuOK以苯为主要产物,还有少量的2,5-二恶双环[4.4.0] -dec-6-ene(6),7和8。提出了这些取代反应的机理。