A Charge-Directed Electrocyclic Ring Opening of Azomethine Ylides as a Route to 2-(N-Acylamino)-1,3-dienes
Abstract
The electrocyclic ring opening of azomethine ylides driven by charge neutralization leads to 2-N-acylamino-1,3-diene products. The requisite azomethine ylide is formed by deprotonation of an oxazolinium ion, which is formed by O-silylation of a readily available oxazolidinone starting material. Computational studies indicate that the deprotonation event is the rate limiting step of the sequence providing a short-lived ylide intermediate that opens spontaneously via a low-barrier (1.7 kcal/mol) transition state leading to an enecarbamate product that is about 48 kcal/mol lower in energy than the ylide intermediate. Charge minimization biases the equilibrium position of the electrocyclization reaction leading to the ring-opened product. This transformation provides a straightforward route to 2-Nsubstituted-N-acylamino-1,3-dienes which were used in subsequent Diels-Alder cycloaddition reactions to give cyclohexenecarbamate products.
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BibTeX
@misc{punjabi2026chargedirected,
title = {{A Charge-Directed Electrocyclic Ring Opening of Azomethine Ylides as a Route to 2-(N-Acylamino)-1,3-dienes}},
author = {Yash Punjabi and Tarun Roy and Roland Tóbiás and Bill Poirier and Matthias Brewer},
howpublished = {ChemRxiv},
year = {2026},
month = oct,
doi = {10.26434/chemrxiv.15009946/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009946/v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - A Charge-Directed Electrocyclic Ring Opening of Azomethine Ylides as a Route to 2-(N-Acylamino)-1,3-dienes
AU - Yash Punjabi
AU - Tarun Roy
AU - Roland Tóbiás
AU - Bill Poirier
AU - Matthias Brewer
PY - 2026
DA - 2026/10/05
PB - ChemRxiv
DO - 10.26434/chemrxiv.15009946/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009946/v1
AB - The electrocyclic ring opening of azomethine ylides driven by charge neutralization leads to 2-N-acylamino-1,3-diene products. The requisite azomethine ylide is formed by deprotonation of an oxazolinium ion, which is formed by O-silylation of a readily available oxazolidinone starting material. Computational studies indicate that the deprotonation event is the rate limiting step of the sequence providing a short-lived ylide intermediate that opens spontaneously via a low-barrier (1.7 kcal/mol) transition state leading to an enecarbamate product that is about 48 kcal/mol lower in energy than the ylide intermediate. Charge minimization biases the equilibrium position of the electrocyclization reaction leading to the ring-opened product. This transformation provides a straightforward route to 2-Nsubstituted-N-acylamino-1,3-dienes which were used in subsequent Diels-Alder cycloaddition reactions to give cyclohexenecarbamate products.
ER -