Ti-catalyzed oxidative alkyne carboamination with alkenes and azo compounds can yield either α,β-unsaturated imines or cyclopropyl imines through a common azatitanacyclohexene intermediate. Herein, we report the synthesis of a model azatitanacyclohexene complex () through the ring-opening of a cyclopropyl imine with CpTi(BTMSA) (BTMSA = bis(trimethylsilyl)acetylene). readily undergoes thermal or reductant-catalyzed ring contraction to an azatitanacyclopentene (), analogous to the proposed mechanism for forming α,β-unsaturated imines in the catalytic reaction. A cyclopropyl imine or an α,β-unsaturated imine could be liberated the oxidation of or with azobenzene, respectively, further implicating the role of these metallacycles in the Ti-catalyzed carboamination reaction.
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| http://dx.doi.org/10.1021/acs.organomet.3c00032 | DOI Listing |
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