102307-46-0Relevant academic research and scientific papers
Insertion of 3,3-dimethylcyclopropenes into the Pd-C bond of cyclopalladated dimethylbenzylamine, leading to C-C bond cleavage or cyclopropyl ring retention. X-ray crystal and molecular structure of [Pd{C(CO2Me)CMe2CHC6H4CH 2NMe2}pyCl]
Maassarani, Fida,Pfeffer, Michel,Le Borgne, Guy,Grandjean, Daniel
, p. 1511 - 1513 (2008/10/08)
When 3,3-dimethylcyclopropenes CR11=CR2CMe2 (where R1, R2 H, CO2Me) are allowed to react with the complex [{Pd(C6H4CH2NMe2)(μ-Cl)}2] (1), insertion into the Pd-C bond of the cyclopalladated dimethylbenzylamine (dmba) takes place to give two types of compound. Opening of the strained ring of the olefin affords monomeric [Pd{(η3-CMe2··CR 2··CR1)C6H4-CH 2NMe2}Cl] (2), whereas simple insertion without C-C bond cleavage leads to dimeric [{Pd(CR1CMe2CR2-C6H 4CH2NMe2)(μ-Cl)}2] (3), in which the cyclopropyl ring is bonded to both the dmba moiety and the Pd atom. With 3,3-dimethylcyclopropene itself (R1 = R2 = H) only compound 2a is obtained, whereas 1 ,2-di-carbomethoxy-3,3-dimethylcyclopropene (R1 = R2 = CO2Me) affords only compound 3a. However, the cyclopropene where R1 = H and R2 = CO2Me gives a mixture of both 2b and 3b in a 1:1 ratio. Compounds 3 react with pyridine in a bridge-splitting reaction to give the monomers 4a and 4b, the latter being fully characterized by an X-ray diffraction study. Crystals of [Pd{C(CO2Me)-CMe2CHC6H4CH 2NMe2}pyCl] (4b) belong to the space group P212121 with a = 12.408 (5) A?, b = 16.315 (4) A?, c = 10.423 (5) A?, v = 2109.9 A?3, and Z = 4. The structure has been refined to R = 0.028 and Rw = 0.038. The pyridine is located trans to the nitrogen atom of the dmba. The cyclopropyl unit is σ-bonded to Pd via the carbon atom which bears the CO2Me group whereas its CH group is bonded to the previously metalated carbon atom of the dmba. The geometry of the new sevenmembered organometallic ring compares favorably with that of related compounds obtained by insertion of alkynes into the Pd-C bond of cyclopalladated dmba.
