Low-valent nickel is shown to preferentially isomerize mono- or disubstituted epoxides into their corresponding aldehydes. Experiments with tetrasubstituted epoxides demonstrate that these reactions proceed via reactive 2-nickelaoxetane intermediates, and that the oxidative addition step likely occurs with retention of configuration. The monosubstituted aldehyde isomerization products were found to rapidly react with HBpin to form boronate esters. These hydroboration reactions could be performed catalytically.
Bibliographical noteFunding Information:
We thank the University of British Columbia (Laird and 4YF to A.N.D. and M.W.D.), NSERC (Discovery grant, Research Tools and Instrumentation grants; CGS-D3 and MSFSS to A.N.D. and M.W.D.) and the Canada Foundation for Innovation for supporting our research. A.N.D. is grateful to the Izaak Walton Killam Foundation for a doctoral scholarship. M.W.D. is grateful to the government of Canada for a Vanier Scholarship. We thank Hironobu Sakaguchi and Desmond Saisitthidej for experimental aid and D. Dawson Beattie for help with X-ray crystallography.