109976-09-2Relevant academic research and scientific papers
Syntheses and Structures of Simple Mono- and Bis(phosphino)allenes
Schmidbaur, Hubert,Pollok, Thomas,Reber, Gabriele,Mueller, Gerhard
, p. 2015 - 2022 (2007/10/02)
Metalation of 1,1-dimethylallene with alkyllithium compounds and treatment of the resulting lithiated products with chlorodiphenylphosphane affords 3,3-dimethyl-1-(diphenylphosphino)allene and -1,1-bis(diphenylphosphino)allene (3 and 8, respectively).The success of the syntheses depends strongly on the reaction conditions.With a change in stoichiometry, temperature, or reaction times, isomeric alkynes (CH3)2CH-C*C-P(C6H5)2 and (C6H5)2P(CH3)2C-C*CH (6 and 7, respectively) are also obtained, and even substitution of phenyl for alkyl groups at the phosphorus atom may occur.Thus the reaction of the intermediate 6 with tert-butyllithium followed by treatment with (C6H5)2PCl leads to the allene (CH3)2C=C=C (12).Through the new preparative methods, mono- and (geminally) bis(phosphino)-substituted allenes have now become easily available in good yields.The prototypes 8 and 12 have been structurally characterized by X-ray diffraction analyses.The molecular conformations are very similar to those of analogous geminal di(phosphino)alkenes.
