Highly Regioselective Ring Opening of Epoxides with Thiols Catalyzed by SbCl3 Under Solvent-Free Conditions

The ring-opening reaction of epoxides with thiols by SbCl ₃ supported on Kieselguhr under solvent-free conditions, afforded high yields of β-hydroxy sulfides. Nucleophilic attack of the thiols occurs regioselectively at the less hindered side of the epoxides.     

Synthesis of Functionalized Novel α‐Amino‐β‐alkoxyphosphonates through Regioselective Ring Opening of Aziridine‐2‐phosphonates

Aziridines are highly useful compounds as building blocks for the synthesis of important organic compounds. Amino acid synthesis by aziridine ring opening reaction is a good example to the use of aziridines. Although this reaction is studied by many groups, the synthesis of amino phosphonic acids is less explored. In this study, we have carried out the ring opening reaction of aziridinyl phosphonates with a variety of alcohols including the more functional propargylic and allylic alcohols. These reactions provided functionalized α‐amino‐β‐alkoxyphosphonates in 40–91 % yield.     

Metal–Organic Frameworks as Efficient Heterogeneous Catalysts for the Regioselective Ring Opening of Epoxides

An iron‐based metal–organic framework, [Fe(BTC)] (BTC: 1,3,5‐benzenetricarboxylate) is an efficient catalyst in the ring opening of styrene oxide with alcohols and aniline under mild reaction conditions. Out of the various alcohols tested for ring opening of styrene oxide, methanol was found to be the most reactive in terms of percentage conversion and reactivity. The rate of the ring‐opening reaction of styrene oxide decreases as the size of the alcohol is increased, suggesting the location of active sites in micropores. [Fe(BTC)] was a truly heterogeneous catalyst and could be reused without loss of activity. The analogous compound [Cu₃(BTC)₂] was also found to be effective, although with somewhat lower activity than [Fe(BTC)]. The present heterogeneous protocol is compared with a homogeneous catalyst to give an insight into the reaction mechanism.