What happens when pyridine N-oxide reacts with dichlorocarbene?

[![reaction scheme](https://i.stack.imgur.com/8oPhL.png)](https://i.stack.imgur.com/8oPhL.png)


It seems that the combination of sodium methoxide (a base) and chloroform will generate dichlorocarbene, $\ce{CCl2}$, by α-elimination.


What happens after that, though? It is an *ortho* formylation like in the Reimer–Tiemann reaction? Or does the nucleophilic oxygen simply attack the carbene?




Dichlorocarbene has been shown to deoxygenate pyridine *N*-oxide producing phosgene as an initial byproduct. In this case, since methoxide is present, dimethyl carbonate is ultimately formed.[1]


The proposed mechanism involves nucleophilic attack on the carbene by the oxygen, followed by an elimination:


[![Mechanism](https://i.stack.imgur.com/m0ukO.png)](https://i.stack.imgur.com/m0ukO.png)


(1) Schweizer, E. E.; O'Neill, G. J. A Novel Deoxygenation Method for Pyridine N-Oxide. *J. Org. Chem.* **1963,** *28* (9), 2460–2461. [DOI: 10.1021/jo01044a516](https://doi.org/10.1021/jo01044a516).


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