Asymmetric Photocyclization of Diarylethene Derivatives
Asymmetric Photocyclization of Diarylethene Derivatives
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DOI：
10.1021/ja970200j
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发表时间：
1997-07
影响因子：
15
通讯作者：
T. Yamaguchi;K. Uchida;M. Irie
中科院分区：
文献类型：
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作者：
T. Yamaguchi;K. Uchida;M. Irie
合成了在苯并[B]噻吩环2-位上具有光学活性的l-或d-薄荷基的二芳基乙烯衍生物。在溶液中用450 nm光照射导致形成闭环形式的非对映体对。非对映异构体的产物比率取决于溶剂极性和温度。在弱极性（或可极化）溶剂中，如THF和甲苯，观察到不对称光环化。在-40 °C的甲苯中，观察到高达86.6%的非对映异构体过量。对不对称光环化反应的机理进行了讨论。
Diarylethene derivatives, which have an optically active l- or d-menthyl group at the 2-position of benzo[b]thiophene ring, were synthesized. Irradiation with 450 nm light in solution led to the formation of diastereomer pairs of the closed-ring forms. The product ratio of the diastereomers was dependent on solvent polarity and temperature. In slightly polar (or polarizable) solvents, such as THF and toluene, an asymmetric photocyclization was observed. At −40 °C in toluene, a diastereomer excess as large as 86.6% was observed. The mechanism of the asymmetric photocyclization is discussed.