Title: Methylene transfer from SnMe groups mediated by a rhodium(I) pincer complex: Sn-C, C-C, and C-H bond activation
Authors : Frech, Christian M.
Shimon, Linda J. W.
Milstein, David
Published in : Chemistry - a European journal
Volume(Issue) : 13
Issue : 26
Pages : 7501
Pages to: 7509
Publisher / Ed. Institution : Wiley
Issue Date: 2007
License (according to publishing contract) : Licence according to publishing contract
Type of review: Peer review (Publication)
Language : English
Subject (DDC) : 540: Chemistry
Abstract: The PCP-Rh(I) complex 1a based on the [1,3-phenylenebis(methylene)]bis(diisopropylphosphine) ligand reacts with [diazo(phenyl)methyl]trimethylstannane (2) at room temperature to give novel pincer-type phenyl(dimethylstannyl)methylene]hydrazinato complex 3a. The reaction sequence involves a unique combination of Sn-C bond cleavage, C-C bond formation, C-H activation and intramolecular deprotonation of a rhodium hydride intermediate, which results in methylene transfer from an SnMe group to the pincer system and PCP-chelate expansion. A methylene-transfer reaction was also demonstrated with tetramethyltin as the methylene source in the presence of KOC(CH(3))(3) at room temperature. The resulting unstable "chelate-expanded" Rh(I) complex [(C(10)H(5)(CH(2)PiPr(2))(2))(CH(2))Rh(L)] (L=N(2), THF; 4a) was isolated as its carbonyl derivative 5a. Heating 4a in benzene yielded an equimolar amount of toluene and 1a, which demonstrates the ability of the Rh(I) pincer complex to extract a methylene group from an unactivated alkyl tin substrate and transfer it, via C-C followed by C-H activation, to an arene. Use of fluorobenzene resulted in formation of fluorotoluene. Catalytic methylene-group transfer mediated by 1a was not possible, because of formation of o-xylylene complex 8 under the reaction conditions. Steric parameters play a decisive role in the reactivity with tin compounds; while iPrP derivative 1 a underwent facile reactions, tBuP complex 1b was inert.
Departement: Life Sciences and Facility Management
Publication type: Article in scientific Journal
DOI : 10.1002/chem.200700320
ISSN: 0947-6539
1521-3765
URI: https://digitalcollection.zhaw.ch/handle/11475/10487
Appears in Collections:Publikationen Life Sciences und Facility Management

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