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Rhodium‐Catalyzed [2+2+2] Cycloaddition Reactions of Linear Allene–Ene–Ynes to afford Fused Tricyclic Scaffolds: Insights into the Mechanism
Author(s) -
Cassú Daniel,
Parella Teodor,
Solà Miquel,
PlaQuintana Anna,
Roglans Anna
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201703194
Subject(s) - allene , cycloaddition , chemistry , rhodium , alkyne , alkene , ene reaction , reactivity (psychology) , double bond , catalysis , stereoselectivity , stereochemistry , organic chemistry , medicine , alternative medicine , pathology
Allene‐( E )‐ene‐yne N ‐tosyl‐tethered substrates 3 a – 3 h were efficiently prepared and their rhodium‐catalyzed [2+2+2] cycloaddition reactions were evaluated. The cycloadditions are chemoselective as only the proximal double bond of the allene reacted to afford exocyclic double bonds in the fused‐tricyclic scaffolds. The stereoselectivity depended on the catalytic system used. Reactivity between allene, alkene, and alkyne was studied for the first time by density functional theory calculations. This mechanistic study determines the order in which the unsaturated groups take part in the catalytic cycle.