Computational explorations of mechanisms and ligand-directed selectivities of copper-catalyzed Ullmann-type reactions.
Computational investigations of ligand-directed selectivities in Ullmann-type coupling reactions of methanol and methylamine with iodobenzene by beta-diketone- and 1,10-phenanthroline-ligated Cu(I) complexes are reported. Density functional theory calculations using several functionals were performed on both the nucleophile formation and aryl halide activation steps of these reactions. The origin of ligand-directed selectivities in N- versus O-arylation reactions as described in a previous publication (J. Am. Chem. Soc. 2007, 129, 3490-3491) were studied and explained. The selectivities observed experimentally are derived not from initial Cu(I)(nucleophile) complex formation but from the subsequent steps involving aryl halide activation. The arylation may occur via single-electron transfer (SET) or iodine atom transfer (IAT), depending on the electron-donating abilities of the ligand and nucleophile. Mechanisms involving either oxidative addition/reductive elimination or sigma-bond metathesis are disfavored. SET mechanisms are favored in reactions promoted by the beta-diketone ligand; N-arylation is predicted to be favored in these cases, in agreement with experimental results. The phenanthroline ligand promotes O-arylation reactions via IAT mechanisms in preference to N-arylation reactions, which occur via SET mechanisms; this result is also in agreement with experimental results.
Jones
Gavin O
GO
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Liu
Peng
P
Houk
K N
KN
Buchwald
Stephen L
SL
D002384:Catalysis; D003198:Computer Simulation; D003300:Copper / Q000737:chemistry*; D007462:Iodobenzenes / Q000737:chemistry*; D008024:Ligands; D000432:Methanol / Q000737:chemistry*; D008744:Methylamines / Q000737:chemistry*; D008956:Models, Chemical; D010618:Phenanthrolines / Q000737:chemistry*
D007462:Iodobenzenes; D008024:Ligands; D008744:Methylamines; D010618:Phenanthrolines; D003300:Copper; C031905:iodobenzene; C027451:methylamine; C025205:1,10-phenanthroline; D000432:Methanol
J Am Chem Soc. 2001 Aug 8;123(31):7727-9
11481007
Phys Rev B Condens Matter. 1988 Jan 15;37(2):785-789
9944570
Chemistry. 2004 Nov 5;10(22):5607-22
15457520
Chem Commun (Camb). 2004 Sep 7;(17):1994-5
15340638
Chem Rev. 2008 Jul;108(7):2180-237
18620366
J Am Chem Soc. 2008 Sep 24;130(38):12762-74
18761460
Org Lett. 2001 Dec 27;3(26):4315-7
11784206
J Am Chem Soc. 2008 Jul 30;130(30):9971-83
18597458
Angew Chem Int Ed Engl. 2010 Mar 15;49(12):2185-9
20198667
J Am Chem Soc. 2002 Oct 2;124(39):11684-8
12296734
Org Lett. 2002 Feb 21;4(4):581-4
11843596
Org Lett. 2002 Oct 17;4(21):3703-6
12375923
J Am Chem Soc. 2007 Nov 14;129(45):13879-86
17941636
J Am Chem Soc. 2007 Mar 28;129(12):3490-1
17341083
J Am Chem Soc. 2006 Jul 12;128(27):8742-3
16819863
J Am Chem Soc. 2009 Jan 14;131(1):78-88
19072233
Org Lett. 2000 May 4;2(9):1333-6
10810741
Chemistry. 2008;14(20):6037-9
18494009
J Am Chem Soc. 2005 Mar 30;127(12):4120-1
15783164
Org Lett. 2003 Mar 20;5(6):793-6
12633073
J Am Chem Soc. 2008 Jul 23;130(29):9196-7
18582057
Org Lett. 2006 Nov 23;8(24):5609-12
17107084
Org Lett. 2003 Jul 10;5(14):2453-5
12841753
J Am Chem Soc. 2009 Dec 2;131(47):17423-9
19899753
J Am Chem Soc. 2002 Jun 26;124(25):7421-8
12071751
J Comput Chem. 2003 Apr 30;24(6):669-81
12666158