Epoxides and Aziridines Written with Prof. Geoffrey W. Coates

Carbonylation of Epoxides and Aziridines (Written with Prof. Geoffrey W. Coates) 

The carbonylation of epoxides and aziridines has been studied for several decades, and two forms of this process are now well established. Highly active catalysts for the ring expansion of epoxides and aziridines to p-lactones and 3-lactams are now known. In addition, conditions have been developed for the hydroformylation of epoxides to a-hydroxy aldehydes (including protected a-hydroxyacetals), and similar conditions have been developed for the tandem hydroformylation and hydrogenation of epoxides to generate 

3- diols. The catalysts for these reactions are either the neutral cobalt carbonyl [COj(CO)J, anionic cobalt carbonyl [Co(CO) ] with a Lewis acidic countercation, or a combination of cobalt and ruthenium carbonyl.  

These reactions are useful as processes to form building blocks for pol)mier s)mthesis and organic s5mthesis. The p-lactones and p-lactams formed by the carbonylation of epoxides and aziridines are monomers that can be used in ring-opening polymerization. The 

3- diols—particularly propanediol—are monomers for large-scale syntheses of polyesters. At the same time, the a-hydroxy aldehydes from epoxide hydroformylation are the equivalent of products from difficult aldol condensations with aldehyde enolates. The advent of methods to prepare or to resolve optically active epoxides has increased the importance of epoxide carbonylation processes for tine-chemical synthesis. 

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