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C(sp 3 )−H Oxidative Addition and Transfer Hydrogenation Chemistry of a Titanium(II) Synthon: Mimicry of Late‐Metal Type Reactivity
Author(s) -
AguilarCalderón J. Rolando,
MettaMagaña Alejandro J.,
Noll Bruce,
Fortier Skye
Publication year - 2016
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201607441
Subject(s) - chemistry , reactivity (psychology) , dehydrogenation , synthon , alkene , photochemistry , metallacycle , cyclohexene , medicinal chemistry , oxidative addition , titanium , metal , cyclohexane , organic chemistry , catalysis , medicine , alternative medicine , pathology , x ray crystallography , physics , diffraction , optics
Two‐electron reduction of the Ti IV compound ( ket guan)(Im Dipp N)Ti(OTf) 2 ( 3 ) gives the arene‐masked complex ( ket guan)(η 6 ‐Im Dipp N)Ti ( 1 ) in excellent yield. Upon standing in solution, 1 converts to a Ti IV metallacycle ( 4 ) through dehydrogenation of a pendant isopropyl group. Spectroscopic evidence shows this transformation initially proceeds via the oxidative addition of a C(sp 3 )−H bond and can be reversed upon exposure of 4 to H 2 . Interestingly, treatment of 1 with cyclohexene gives cyclohexane and 4 via a titanium‐mediated transfer hydrogenation reaction, a process that can be extended to catalytically hydrogenate other unsaturated hydrocarbons under mild conditions. These results, rare for the early‐metals, suggest 1 possesses chemical characteristics reminiscent of noble, late‐metals.