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 04:00:00 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), Journal Name: Organometallics; (United States) Vol. 14:2; ISSN 0276-7333; ISSN ORGND7
• Country of Publication: United States
• Language: English

Related Subjects

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