Energy Transfer (EnT) Catalysed [4+2] Cycloaddition of Non-Symmetrical Dienes: From Mechanistic Anomaly to Fully Functional Reaction Pathway
Abstract
Harnessing the reactivity of triplet biradicals to selectively access unconventional cycloaddition pathways remains a fundamental challenge in energy transfer (EnT) catalysis. Herein, we demonstrate that systematic variation of diene substitution can redirect the intrinsic [2+2] reactivity of non-symmetrical dienes towards highly selective [4+2] cycloaddition. Notably, incorporation of a traceless vicinal BPin group invokes a non-conventional [4+2] pathway providing polysubstituted cyclohexenes with excellent regio- and diastereoselectivity. Mechanistic and computational investigations reveal that A-1,3-strain and geometric isomerisation shape the conformational landscape of the triplet biradical, accounting for the observed divergent reactivity. These findings establish substitution-controlled excited-state conformational dynamics as a key parameter for directing EnT-mediated cycloadditions beyond conventional [2+2] reactivity.
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BibTeX
@misc{kortman2026energy,
title = {{Energy Transfer (EnT) Catalysed [4+2] Cycloaddition of Non-Symmetrical Dienes: From Mechanistic Anomaly to Fully Functional Reaction Pathway}},
author = {Hannah M. Kortman and Alessia Marrese and Aimara García-Camacho and Yu Jen Hsueh and Paul Aßmann and Hao Fang and Anja Wiesner and Peter H. Seeberger and Diego Sampedro and Ignacio Funes-Ardoiz and John James Molloy},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15008339/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008339/v1},
note = {CC BY-NC},
}
RIS
TY - UNPB
TI - Energy Transfer (EnT) Catalysed [4+2] Cycloaddition of Non-Symmetrical Dienes: From Mechanistic Anomaly to Fully Functional Reaction Pathway
AU - Hannah M. Kortman
AU - Alessia Marrese
AU - Aimara García-Camacho
AU - Yu Jen Hsueh
AU - Paul Aßmann
AU - Hao Fang
AU - Anja Wiesner
AU - Peter H. Seeberger
AU - Diego Sampedro
AU - Ignacio Funes-Ardoiz
AU - John James Molloy
PY - 2026
DA - 2026/09/04
PB - ChemRxiv
DO - 10.26434/chemrxiv.15008339/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008339/v1
AB - Harnessing the reactivity of triplet biradicals to selectively access unconventional cycloaddition pathways remains a fundamental challenge in energy transfer (EnT) catalysis. Herein, we demonstrate that systematic variation of diene substitution can redirect the intrinsic [2+2] reactivity of non-symmetrical dienes towards highly selective [4+2] cycloaddition. Notably, incorporation of a traceless vicinal BPin group invokes a non-conventional [4+2] pathway providing polysubstituted cyclohexenes with excellent regio- and diastereoselectivity. Mechanistic and computational investigations reveal that A-1,3-strain and geometric isomerisation shape the conformational landscape of the triplet biradical, accounting for the observed divergent reactivity. These findings establish substitution-controlled excited-state conformational dynamics as a key parameter for directing EnT-mediated cycloadditions beyond conventional [2+2] reactivity.
ER -