| Abstract
| - The regioselective ring-opening reactions of some epoxides with ammonium thiocyanate in thepresence of a series of new phenol-containing macrocyclic diamides and also dibenzo-18-crown-6-,18-crown-6-, benzo-15-crown-5-, and pyridine-containing macrocyclic diamide have been studied.The epoxides were subject to cleavage by NH4SCN in the presence of these catalysts under mildreaction conditions in various aprotic solvents. In this study, reagents and conditions have beendiscovered with which the individual β-hydroxy thiocyanates can be synthesized in high yield andwith more than 90% regioselectivity. The results can be discussed in terms of a four-stepmechanism: (1) formation of complex between catalyst and NH4SCN, (2) release of SCN- nucleophilefrom the complex, (3) reaction of the active nucleophile at the less sterically hindered site in theepoxide, and (4) regeneration of catalyst. The major advantages of this method are as follows: (1)high regioselectivity, (2) simple regeneration of catalyst, (3) its reuse through several cycles withouta decrease in activity, and (4) ease of workup of the reaction.
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