A simple and highly efficient synthesis of beta, beta'-dihydroxy sulfides has been achieved by ring opening of epoxides with mercaptoethanol using catalytic amount of benzyltrimethylammonium hydroxide (Triton B) under solvent-free conditions. Excellent regioselectivity was found for aliphatic unsymmetrical epoxides, with nucleophilic attack at the less-hindered carbon atom of the epoxide. However, this regioselectivitywas not observed for styrene oxide and a mixture of two isomers was obtained. This process was also regio- and chemo-selective as illustrated using epichlorohydrin with two epoxide ring positions and mercaptoethanol with two functional groups (SH and OH).[GRAPHICS].1a-e 2ae(1)(alpha) 2e(2)(beta)R = CH3(a) ; C2H3(b) ; CICH2(c) ; PhOCH2(d) ; ph(e).
Routes for reactions of alkylene oxides with R-β-hydroxyalkyl sulfides: Unusual exchange of functional groups
作者:A. D. Malievskii
DOI:10.1134/s0965544112010069
日期:2012.5
Possible routes of the previously unknown exchange reaction of alkylene oxides with R-beta-hydroxyalkyl sulfides have been considered. Each route has intermediates and transition states of its own, but all the directions in the final stage lead to the formation of a single intermediate cyclic bipolar ion with intramolecular hydrogen bonding, which determines the common nature and composition of end products for all routes. The features of the reaction have been analyzed. The quantitative description of each route has been given.
Efficient Synthesis of <font>β</font>-Hydroxy Sulfides and <font>β</font>-Hydroxy Sulfoxides Catalyzed by Cu/MgO Under Solvent-Free Conditions
Regio-, stereo-, and chemoselectivering opening of epoxides with thiols using Cu/MgO as a heterogeneous catalyst has efficiently been carried out to produce the corresponding β-hydroxy sulfides in excellent yields at room temperature under solvent-free conditions. The treatment of the epoxides with thiols and 50% aqueous H2O2 in the presence of the same catalyst at room temperature affords the β-hydroxy