Premium
Reaction of Aryl Iodides with (PCP)Pd(II)—Alkyl and Aryl Complexes: Mechanistic Aspects of Carbon—Carbon Bond Formation
Author(s) -
Kraatz HeinzBernhard,
van der Boom Milko E.,
BenDavid Yehoshoa,
Milstein David
Publication year - 2002
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1560/v0q8-t3xm-n68w-d8nl
Subject(s) - chemistry , aryl , iodide , medicinal chemistry , radical , toluene , biphenyl , alkyl , photochemistry , organic chemistry
The reaction of the PCP‐type complex Pd(Me){2,6‐( i Pr 2 PCH 2 ) 2 C 6 H 3 }( 3 ) with phenyl iodide results in the formation of Pd(I){2,6‐( i Pr 2 PCH 2 ) 2 C 6 H 3 } ( 5 ), methyl iodide, toluene, and biphenyl. Formation of Pd(Ph){2,6‐( i Pr 2 PCH 2 ) 2 C 6 H 3 }( 4 ) is observed during the reaction by 31 P NMR. Reaction of 4 with aryl iodides results in the formation of 5 and Ph–Ph, Ph–Ar, and Ar–Ar, products indicative of a radical reaction. Under pseudo‐first‐order conditions, the rates of the reactions follow the order p ‐OMe > p ‐Me > H > p ‐NO 2 > m ‐Cl. The reaction is likely to involve electron transfer from 4 to the aryl iodide followed by fast decomposition of a postulated radical cation [Pd(Ph){2,6‐( i Pr 2 PCH 2 ) 2 C 6 H 3 }] +. ( 4 +. ) to give a phenyl radical and [Pd{2,6‐( i Pr 2 PCH 2 ) 2 C 6 H 3 }] + ( 6 + ). Facile decomposition of the aryl iodide radical anion generates an aryl radical and I − . Recombination of aryl radicals gives rise to mixed biaryls, and 6 + combines with I − to give 5 .