在无溶剂条件下,三氟甲磺酸镓(III)催化环氧化物的开环可提供具有高区域选择性和化学选择性的β-羟基硫化物,产率高(84-97%)。另外,首次开发了在单一水中合成β-羟基亚砜的简单,有效且对环境无害的一锅法。通过H 2 O 2 -Ga(OTf)3系统的促进,该过程以高收率(81-94%)和高化学选择性提供了β-羟基亚砜,而没有检测到对β-羟基砜的过度氧化。反应后催化剂可以容易地回收并重新使用而没有明显的活性损失。
Rongaliteo (R) promotes cleavage of disulfides generating thiolate anions that then undergo facile ring opening of epoxides in the presence of K2CO3 to afford alpha-addition products 3 with good to excellent yields. The important features of this methodology are broad substrates scope, high yielding, reasonably rapid reaction rate, high regioselectivity and no requirement of metal catalysts. It should be noted that the thiolate anion attacks the epoxides derived from styrene to produce the corresponding alpha-addition products 3 with high regioselectivity, instead of the beta-addition regioisomer 4 that Could be formed from the attack of the nucleophile at the benzylic position. (C) 2009 Elsevier Ltd. All rights reserved.