New alkene carbon-hydrogen bond activation reaction. Facile and stereospecific vinylic deprotonation of the chiral cationic rhenium alkene complexes [([eta][sup 5]-C[sub 5]H[sub 5])Re(NO)(PPh[sub 3])(H[sub 2]C=CHR)][sup +] BF[sub 2][sup -]

Journal Article · Wed Feb 01 00:00:00 EST 1995 · Organometallics; (United States)

DOI:https://doi.org/10.1021/om00002a042· OSTI ID:6492618

Peng, T S; Gladysz, J A ^[1]

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1. Univ. of Utah, Salt Lake City, UT (United States)

Alkene complexes [([eta][sup 5]-C[sub 5]H[sub 3])Re(NO)(PPh[sub 3])H[sub 2]C=CHR][sup +] BF[sub 4][sup -] 1; R = a, CH[sub 3]; b, CH[sub 2]CH[sub 2]-CH[sub 3]; c, CH(CH[sub 3])[sub 2]; d, H; e, C[sub 6]H[sub 5]; f, C(CH[sub 3])[sub 3]; [ge] 96:4 RS,SR/RR,SS Re,C configurational diastereomers and t-BuO K[sup -] react in THF to give alkenyl complexes ([eta][sup 5]-C[sub 5]H[sub 5])Re(NO)(PPh[sub 3])-CH=CHR) (2; 83-98% after workup). Allylbenzene complex 1g (R = CH[sub 2]C[sub 6]H[sub 5]) gives a 89:11 mixture (91%) of 2g and allyl complex ([eta][sup 5]-C[sub 5]H[sub 5])Re(NO)(PPh[sub 3])(CH[sub 2]CH=CHR[prime]) (3g). The 2g:3g ratio decreases when t-BuOH solvent or (RR,SS)-1g is used - conditions that also give 2a,b/3a,b mixtures. NMR experiments show that (RS,SR)- and (RR,SS)-1 give (E)- and (Z)-2, respectively. However, the latter equilibrate (K[sub eq] [ge] (99-82):(<1-18)) at room temperature. Deuterium labeling shows that only one germinal =CH[sub 2] proton is abstracted from each diastereomer, as controlled by the rhenium configuration (H[sub S] from (RS)- or (RR)-1). Deprotonation is irreversible and occurs with retention at rhenium, with a k[sub H]/k[sub D] value of 1.7 and without PPh[sub 3] dissociation. A Rh(I) catalyst shows 2a to be more stable than 3a, but no isomerization occurs under the deprotonation conditions. 61 refs., 1 fig.

• OSTI ID: 6492618
• Journal Information: Organometallics; (United States), Vol. 14:2; ISSN 0276-7333
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ORGANOMETALLIC COMPOUNDS
CHEMICAL REACTIONS
NMR SPECTRA
SYNTHESIS
RHENIUM COMPLEXES
ALKENES
CHEMICAL BONDS
CHIRALITY
COMPLEXES
HYDROCARBONS
ORGANIC COMPOUNDS
PARTICLE PROPERTIES
SPECTRA
TRANSITION ELEMENT COMPLEXES
400201* - Chemical &amp; Physicochemical Properties
400102 - Chemical &amp; Spectral Procedures