210840-53-2Relevant academic research and scientific papers
Single and multiple insertion of arylallene into the Rh-H bond to give (π-Allyl)rhodium complexes
Choi, Jun-Chul,Osakada, Kohtaro,Yamamoto, Takakazu
, p. 3044 - 3050 (2008/10/08)
The reaction of RhH(PPh3)4 at room temperature with excess phenylallene, (4-methylphenyl)allene, (4-methoxyphenyl)allene, (4-tert-butylphenyl)allene, (4-chlorophenyl)allene, and (4-fluorophenyl)allene results in the insertion of four arylallene molecules into the Rh-H bond to afford Rh{η3-CH2C[CH(Ar)]C(=CHAr)CH 2C(=CHAr)CH2CH2CH=CHAr)}(PPh3) 2 (1, Ar = C6H5; 2, Ar = C6H4Me-P; 3, Ar = C6H4OMe-p; 4, Ar = C6H4-t-Bu-p; 5, Ar = C6H4Cl-p; 6, Ar = C6H4F-p), respectively. NMR (1H, 13C, and 31P) spectroscopy was used to characterize the (π-allyl)rhodium(I) complexes. Reaction of (4-methoxyphenyl)allene with RhD(PPh3-d15)4 gives 3-d31, Rh{η3-CH2C[CH(Ar)]C(=CHAr)CH 2C(=CHAr)CH2CH2CD=CHAr)}(PPh3-d 15)2 (Ar = C6H4OMe-p), whose vinylene hydrogen is deuterated selectively. Complexes 1 and 3 do not react further with arylallene at room temperature. Reaction of arylallenes with an equimolar amount of RhH(CO)(PPh3)3 leads to the insertion of a molecule into the Rh-H bond to give the (π-allyl)rhodium complexes Rh(η3-CH2CHCHC6H 4X-p)(CO)(PPh3)2 (9, X = Me; 10, X = OMe; 11, X = F; 12, X = Cl), while excess phenylallene reacts with the hydridorhodium complex to give a mixture of 1, Rh(η3-CH2CHCHPh)(CO)(PPh3)2, and unreacted RhH(CO)(PPh3)3. A crystallographic study of 9 and 1H NMR data for the complexes indicate that the aryl substituent has a syn orientation. The π-allyl complexes react with monosubstituted acetylenes to give trans-Rh(C≡CZ)(CO)(PPh3)2 (13, Z = Ph; 14, Z = C6H4Me-p; 15, Z = SiMe3) accompanied by the generation of 1-arylpropene.
