10.1021/om049632a.s001
Masumi Itazaki
Masumi
Itazaki
Chikako Yoda
Chikako
Yoda
Yasushi Nishihara
Yasushi
Nishihara
Kohtaro Osakada
Kohtaro
Osakada
C−C and C−H Bond Activation of
Dialkylmethylenecyclopropane Promoted by Rhodium
and Iridium Complexes. Preparation and Structures of
M(η<sup>1</sup>:η<sup>2</sup>-CH<sub>2</sub>CR<sub>2</sub>CHCH<sub>2</sub>)(CO)(PPh<sub>3</sub>)<sub>2</sub> and
<i>trans</i>-M(CHCHCMeR<sub>2</sub>)(CO)(PPh<sub>3</sub>)<sub>2</sub> (M = Rh, Ir, R =
CH<sub>2</sub>CH<sub>2</sub>Ph)
American Chemical Society
2004
reaction mechanisms
Dialkylmethylenecyclopropane Promoted
alkenyl complexes trans
Heating 1
HC
H 2
MH
Iridium Complexes
η 2
CO
2 CH 3
CR
NMR
η 1
oxidative addition
alkynyl complexes trans
metal center
room temperature
CH 2 CH 2 Ph
2004-11-08 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/C_C_and_C_H_Bond_Activation_of_Dialkylmethylenecyclopropane_Promoted_by_Rhodium_and_Iridium_Complexes_Preparation_and_Structures_of_M_sup_1_sup_sup_2_sup_CH_sub_2_sub_CR_sub_2_sub_CH_CH_sub_2_sub_CO_PPh_sub_3_sub_sub_2_sub_and_i_trans_i_M_CH_CHCMeR_sub_2_/3317173
2,2-Bis(2-phenylethyl)-1-methylenecyclopropane reacts with RhH(CO)(PPh<sub>3</sub>)<sub>3</sub> at room
temperature and with IrH(CO)(PPh<sub>3</sub>)<sub>3</sub> at 70 °C to form the 3-butenyl complexes of these
metals, M{<i>η</i><sup>1</sup>:<i>η</i><sup>2</sup>-CH<sub>2</sub>C(CH<sub>2</sub>CH<sub>2</sub>Ph)<sub>2</sub>CHCH<sub>2</sub>}(CO)(PPh<sub>3</sub>)<sub>2</sub> (<b>1</b>, M = Rh;<b> 2</b>, M = Ir). Heating <b>1</b>
at 55 °C liberates 1,1-bis(2-phenylethyl)-1,3-butadiene, while the thermal reaction of <b>2</b> at
110 °C forms a mixture of 3-methyl-3-vinyl-1,5-diphenyl-1-pentene (48% NMR yield) and
3-methyl-3-vinyl-1,5-diphenylpentane (15% NMR yield). The reactions of excess amounts of
2,2-bis(2-phenylethyl)-1-methylenecyclopropane with RhH(CO)(PPh<sub>3</sub>)<sub>3</sub> at 55 °C and with IrH(CO)(PPh<sub>3</sub>)<sub>3</sub> at 115 °C afford the alkenyl complexes <i>trans</i>-Rh{(<i>Z</i>)-CHCHC(CH<sub>2</sub>CH<sub>2</sub>Ph)<sub>2</sub>CH<sub>3</sub>}(CO)(PPh<sub>3</sub>)<sub>2</sub> (<b>3</b>) and <i>trans</i>-Ir{(<i>E</i>)-CHCHC(CH<sub>2</sub>CH<sub>2</sub>Ph)<sub>2</sub>CH<sub>3</sub>}(CO)(PPh<sub>3</sub>)<sub>2</sub> (<b>4</b>), respectively.
The reaction mechanisms are discussed on the basis of the results of the reactions under
different conditions. HC⋮CC(CH<sub>2</sub>CH<sub>2</sub>Ph)<sub>2</sub>CH<sub>3</sub> reacts with MH(CO)(PPh<sub>3</sub>)<sub>3</sub> (M = Rh, Ir) to
afford the alkynyl complexes <i>trans</i>-M{C⋮CC(CH<sub>2</sub>CH<sub>2</sub>Ph)<sub>2</sub>CH<sub>3</sub>}(CO)(PPh<sub>3</sub>)<sub>2</sub> (<b>5</b>, M = Rh;<b> 6</b>,
M = Ir) via oxidative addition of the C(alkyne)−H bond to the metal center and subsequent
elimination of H<sub>2</sub>.