1-Ethynyl-2-methylcyclohex-1-ene, hitherto obtained only as a mixture with one of its double-bond isomers, is obtained pure by dehydrohalogenation of ω-halogenodienes such as 1-(2-chlorovinyl)-2-methylcyclohexene (6; X = Cl). The optically active 5-hydroxy-2-methylcyclohex-1-enecarbaldehyde (10) reacts with chloromethylenetriphenylphosphorane giving mixed cis- and trans-ω-chloro-dienes [cf.(11)], dehydrohalogenation
迄今仅以与其双键异构体之一的混合物形式获得的1-
乙炔基-2-甲基环己-1-烯是通过ω-卤代二烯如1-(2-
氯乙烯基)-2-甲基
环己烯( 6; X = Cl)。旋光的5-羟基-2-甲基环己-1-烯
甲醛(10)与
氯亚甲基三苯基
磷烷反应,生成混合的顺式和反式-ω-
氯二烯[ cf. (11)],其脱卤化氢得到标题化合物(12),其是合成
钙化前醇3所必需的。