TY  - JOUR
A1  - Maier, Jan
A1  - Marder, Todd B.
T1  - Mechanistic and Kinetic Factors of ortho‐Benzyne Formation in Hexadehydro‐Diels‐Alder (HDDA) Reactions
JF  - Chemistry – A European Journal
N2  - With the rapid development of the hexadehydro‐Diels‐Alder reaction (HDDA) from its first discovery in 1997, the question of whether a concerted or stepwise mechanism better describes the thermally activated formation of ortho‐benzyne from a diyne and a diynophile has been debated. Mechanistic and kinetic investigations were able to show that this is not a black or white situation, as minor changes can tip the balance. For that reason, especially, linked yne‐diynes were studied to examine steric, electronic, and radical‐stabilizing effects of their terminal substituents on the reaction mechanism and kinetics. Furthermore, the influence of the nature of the linker on the HDDA reaction was explored. The more recently discovered photochemical HDDA reaction also gives ortho‐arynes, which display the same reactivity as the thermally generated ones, but their formation might not proceed by the same mechanism. This minireview summarizes the current state of mechanistic understanding of the HDDA reaction.
KW  - Alkyne
KW  - Benzyne
KW  - Cyclization
KW  - Hexadehydro-Diels-Alder
KW  - reaction mechanism
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-239006
VL  - 27
IS  - 30
SP  - 7978
EP  - 7991
ER  -