Stereoselective synthesis of tetrahydrofurans and tetrahydropyrans by acid-catalyzed cyclization of hydroxy selenides and hydroxy sulfides
作者:Michelangelo Gruttadauria、Paolo Lo Meo、Renato Noto
DOI:10.1016/s0040-4020(99)00876-5
日期:1999.12
compounds 1a and 1′a allowed the stereoselective synthesis of a substituted tetrahydrofuran ring, whereas compounds 1b-c and 1′b-c gave an efficient regiochemical control affording substituted tetrahydropyran rings. Tetrahydropyrans containing the phenylselanyl moiety were found to be in equilibrium in the cyclization reaction conditions, whereas tetrahydropyrans containing the phenylsulfanyl moiety were
研究了羟基硒化物和羟基硫化物(1a-c和1'ac)在酸性介质中的行为。化合物1a和1'a中伯羟基的保护允许立体选择性合成取代的四氢呋喃环,而化合物1b-c和1'bc提供了有效的区域化学控制,提供了取代的四氢吡喃环。发现在环化反应条件下,含有苯硒基部分的四氢吡喃处于平衡状态,而含有苯硫基部分的四氢吡喃则没有平衡。提出了上述平衡的机制。半经验的(AM1,PM3)和从头算起(HF / 3-21G ∗)计算用于合理化实验结果。