One-Pot Catalytic Conversion of Epoxides to 1,2-Diacetates with Hydride Transferring Agents in Acetic Anhydride

Abstract

Direct transformation of structurally different epoxides to the corresponding 1,2-diacetates was studied with catalytic amounts of NaBH₄, LiAlH₄, CaH₂, and NaH. The reactions were carried out in refluxing acetic anhydride within 1.5–2.5 h to give vic-diacetates in good to excellent yields. Conversion of R-(+)-styrene oxide to S-(+)-1,2-diacetoxy-1-phenylethane was carried out with good yield and stereospecificity with the NaBH₄/Ac₂O system at 0 °C.

Keywords:

• CaH₂
• 1,2-diacetate
• epoxide
• LiAlH₄
• NaBH₄
• NaH

ACKNOWLEDGMENT

We acknowledge the financial support of this work by the Research Council of Urmia University.

Notes

^a All reactions were carried out in the presence of NaBH₄ (0.2 eq) in refluxing Ac₂O (1 mL).

^b Yields refer to isolated pure products.

^a All reactions were carried out with 0.2 eq hydride reagents in refluxing Ac₂O (1 mL).

^b Yields refer to isolated pure products.

^a Amount of catalyst per 1 mmol of epoxide.

^b Reaction time was not reported, however, 24 h was the reported time for ring openning–acetolysis of N-tosylaziridines.

^c No reaction occured on aromatic epoxides.