Carbon-carbon bond activation by Rhodium(I) in solution. Comparison of sp2-sp3 vs sp3-sp3 C-C, C-H vs C-C, and Ar-CH3 vs Ar-CH2CH3 activation

Milko van der Boom, Shyh Yeon Liou, Yehoshoa Ben-David, Michael Gozin, David Milstein

Research output: Contribution to journalArticle

72 Citations (Scopus)

Abstract

Reaction of [RhCIL2]2 (L = cyclooctene or ethylene) with 2 equiv of the phosphine {1-Et-2,6(CH2P(t)Bu2)2C6H3} (1) in toluene results in a selective metal insertion into the strong Ar-Et bond. This reaction proceeds with no intermediacy of activation of the weaker sp3-sp3 ArCH2-CH3 bond. The identity of complex Rh(Et){2,6-(CH2P(t)Bu2)2C6H3}Cl (3) was confirmed by preparation of the iodide analogue 6 by reaction of the new Rh(η(I)-N2){2,6-(CH2P(t)Bu2)2C6H3} (7) with EtI. It is possible to direct the bond activation process toward the benzylic C-H bonds of the aryl- alkyl group by choice of the Rh(I) precursor, of the substituents on the phosphorus atoms ((t)Bu vs Ph), and of the alkyl moiety (Me vs Et). A Rh(III) complex which is analogous to the product of insertion into the ArCH2-CH3 bond (had it taken place) was prepared and shown not to be an intermediate in the Ar-CH2CH3 bond activation process. Thus, aryl-C activation by Rh(I) is kinetically preferred over activation of the alkyl-C bond in this system. Moreover, cleavage of an Ar-CH2CH3 bond, followed by β-H elimination, may be preferred over sp2-sp3 C-C activation of an Ar-CH3 group.

Original languageEnglish
Pages (from-to)13415-13421
Number of pages7
JournalJournal of the American Chemical Society
Volume120
Issue number51
DOIs
Publication statusPublished - Dec 30 1998

Fingerprint

phosphine
Rhodium
Toluene
Iodides
Phosphorus
Carbon
Metals
Chemical activation
ethylene
Ethylene

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Carbon-carbon bond activation by Rhodium(I) in solution. Comparison of sp2-sp3 vs sp3-sp3 C-C, C-H vs C-C, and Ar-CH3 vs Ar-CH2CH3 activation. / van der Boom, Milko; Liou, Shyh Yeon; Ben-David, Yehoshoa; Gozin, Michael; Milstein, David.

In: Journal of the American Chemical Society, Vol. 120, No. 51, 30.12.1998, p. 13415-13421.

Research output: Contribution to journalArticle

@article{81280193c31a45e786e901497c3ae51a,
title = "Carbon-carbon bond activation by Rhodium(I) in solution. Comparison of sp2-sp3 vs sp3-sp3 C-C, C-H vs C-C, and Ar-CH3 vs Ar-CH2CH3 activation",
abstract = "Reaction of [RhCIL2]2 (L = cyclooctene or ethylene) with 2 equiv of the phosphine {1-Et-2,6(CH2P(t)Bu2)2C6H3} (1) in toluene results in a selective metal insertion into the strong Ar-Et bond. This reaction proceeds with no intermediacy of activation of the weaker sp3-sp3 ArCH2-CH3 bond. The identity of complex Rh(Et){2,6-(CH2P(t)Bu2)2C6H3}Cl (3) was confirmed by preparation of the iodide analogue 6 by reaction of the new Rh(η(I)-N2){2,6-(CH2P(t)Bu2)2C6H3} (7) with EtI. It is possible to direct the bond activation process toward the benzylic C-H bonds of the aryl- alkyl group by choice of the Rh(I) precursor, of the substituents on the phosphorus atoms ((t)Bu vs Ph), and of the alkyl moiety (Me vs Et). A Rh(III) complex which is analogous to the product of insertion into the ArCH2-CH3 bond (had it taken place) was prepared and shown not to be an intermediate in the Ar-CH2CH3 bond activation process. Thus, aryl-C activation by Rh(I) is kinetically preferred over activation of the alkyl-C bond in this system. Moreover, cleavage of an Ar-CH2CH3 bond, followed by β-H elimination, may be preferred over sp2-sp3 C-C activation of an Ar-CH3 group.",
author = "{van der Boom}, Milko and Liou, {Shyh Yeon} and Yehoshoa Ben-David and Michael Gozin and David Milstein",
year = "1998",
month = "12",
day = "30",
doi = "10.1021/ja982345b",
language = "English",
volume = "120",
pages = "13415--13421",
journal = "Journal of the American Chemical Society",
issn = "0002-7863",
publisher = "American Chemical Society",
number = "51",

}

TY - JOUR

T1 - Carbon-carbon bond activation by Rhodium(I) in solution. Comparison of sp2-sp3 vs sp3-sp3 C-C, C-H vs C-C, and Ar-CH3 vs Ar-CH2CH3 activation

AU - van der Boom, Milko

AU - Liou, Shyh Yeon

AU - Ben-David, Yehoshoa

AU - Gozin, Michael

AU - Milstein, David

PY - 1998/12/30

Y1 - 1998/12/30

N2 - Reaction of [RhCIL2]2 (L = cyclooctene or ethylene) with 2 equiv of the phosphine {1-Et-2,6(CH2P(t)Bu2)2C6H3} (1) in toluene results in a selective metal insertion into the strong Ar-Et bond. This reaction proceeds with no intermediacy of activation of the weaker sp3-sp3 ArCH2-CH3 bond. The identity of complex Rh(Et){2,6-(CH2P(t)Bu2)2C6H3}Cl (3) was confirmed by preparation of the iodide analogue 6 by reaction of the new Rh(η(I)-N2){2,6-(CH2P(t)Bu2)2C6H3} (7) with EtI. It is possible to direct the bond activation process toward the benzylic C-H bonds of the aryl- alkyl group by choice of the Rh(I) precursor, of the substituents on the phosphorus atoms ((t)Bu vs Ph), and of the alkyl moiety (Me vs Et). A Rh(III) complex which is analogous to the product of insertion into the ArCH2-CH3 bond (had it taken place) was prepared and shown not to be an intermediate in the Ar-CH2CH3 bond activation process. Thus, aryl-C activation by Rh(I) is kinetically preferred over activation of the alkyl-C bond in this system. Moreover, cleavage of an Ar-CH2CH3 bond, followed by β-H elimination, may be preferred over sp2-sp3 C-C activation of an Ar-CH3 group.

AB - Reaction of [RhCIL2]2 (L = cyclooctene or ethylene) with 2 equiv of the phosphine {1-Et-2,6(CH2P(t)Bu2)2C6H3} (1) in toluene results in a selective metal insertion into the strong Ar-Et bond. This reaction proceeds with no intermediacy of activation of the weaker sp3-sp3 ArCH2-CH3 bond. The identity of complex Rh(Et){2,6-(CH2P(t)Bu2)2C6H3}Cl (3) was confirmed by preparation of the iodide analogue 6 by reaction of the new Rh(η(I)-N2){2,6-(CH2P(t)Bu2)2C6H3} (7) with EtI. It is possible to direct the bond activation process toward the benzylic C-H bonds of the aryl- alkyl group by choice of the Rh(I) precursor, of the substituents on the phosphorus atoms ((t)Bu vs Ph), and of the alkyl moiety (Me vs Et). A Rh(III) complex which is analogous to the product of insertion into the ArCH2-CH3 bond (had it taken place) was prepared and shown not to be an intermediate in the Ar-CH2CH3 bond activation process. Thus, aryl-C activation by Rh(I) is kinetically preferred over activation of the alkyl-C bond in this system. Moreover, cleavage of an Ar-CH2CH3 bond, followed by β-H elimination, may be preferred over sp2-sp3 C-C activation of an Ar-CH3 group.

UR - http://www.scopus.com/inward/record.url?scp=0032583540&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0032583540&partnerID=8YFLogxK

U2 - 10.1021/ja982345b

DO - 10.1021/ja982345b

M3 - Article

VL - 120

SP - 13415

EP - 13421

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 51

ER -