Ring-Opening of Vinyl Epoxides with Heteroatom Nucleophiles

Ring-Opening of Vinyl Epoxides with Heteroatom Nucleophiles 

8 Ring-Opening of Vinyl Epoxides with Heteroatom Nucleophiles 433 vinyl epoxide product 

5- and 6-membered heteroqrdes by this approach, Ha noted that trans, trans-vinyl epoxide 74 undergoes intramolecular addition in the presence of [Rh(CO)2Cl]2 to afford piperidine 75, whereas the corresponding cis, trans-vinyl epoxide 76 failed to cydize under the same reaction conditions [28]. The latter was attributed to the inability of rhodium to simultaneously coordinate the alkene and oxygen atom with the requisite geometry for the oxidative addition step. The position of the alkene was shown to be important as the intermolecular reaction of exo-methylene cydohexene oxide 77 with MeOH failed to generate 79, and resulted in intractable mixtures. Presumably, the more rigid framework of 78 does not allow isomerization to the oxametallacycle. 

We thank the coworkers named in the references for their intellectual and experimental contributions. Tomislav Rovis and Keith Fagnou deserve special mention for their seminal discoveries. We thank Andrew Martins and Hans-Ulrich Blaser (Solvias AG) for helpful discussions when preparing this manuscript We thank AstraZeneca, the ORDCF, the University of Toronto and NSERC for financial support 

16 Wilkinson, G. (1982) Comprehensive Organometallic Chemistry, Pergamon Press, vol. 5. 

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