Extremely Efficient Cross‐Coupling of Benzylic Halides with Aryltitanium Tris(isopropoxide) Catalyzed by Low Loadings of a Simple Palladium(II) Acetate/Tris(p‐tolyl)phosphine System

Abstract

Highly efficient coupling reactions of benzylic bromides or chlorides with aryltitanium tris(isopropoxide) [ArTi(O-i-Pr)(3)] catalyzed by a simple palladium(II) acetate/tris(p-tolyl)phosphine [Pd(OAc)(2)/P(p-tolyl)(3)] system are reported. The coupling reactions proceed in general at room temperature employing low catalyst loadings of 0.02 to 0.2 mol%, affording coupling products in excellent yields of up to 99%. For benzylic bromides bearing strong electron-withdrawing cyano (CN) or trifluoromethyl (CF(3)) substituents, the reactions require a higher catalyst loading of 1 mol%, or the reactions are carried out at 60 degrees C. The catalytic system also tolerates (1-bromoethyl)benzene bearing beta-hydrogen atoms while using a catalyst loading of 1 mol% to afford the coupling product in a 70% yield

Iron‐Catalyzed Arylation of Aromatic Ketones and Aldehydes Mediated by Organosilanes

“…R f = 0.58 (dichloromethane/hexane, 1:3). Characterization data is consistent with that published previously 40…”

Chlorotrimethylsilane and Sodium Iodide: A Remarkable Metal‐Free Association for the Desulfurization of Benzylic Dithioketals under Mild Conditions

“…HRMS (APCI): m/z [M+H] + calcd for C17H19S2: 287.0923; found: 287.0933. -2-(o-tolyl) Phenyl-1,3-dithian-2-yl) Diphenylmethane (7a) [25] : Colorless oil, for yield: see the text. 2903, 1600, 1494, 1479, 1452, 1396, 1367, 1276, 1175, 1093, 1072, 1030, 1012, 907, 867, 833, 801, 737, 699 cm -1 .…”

Room temperature and highly enantioselective additions of alkyltitanium reagents to aldehydes catalyzed by a titanium catalyst of (R)‐h8‐binol

“…42 Recently, we had successfully synthesized [(3-furyl)Ti(O-i-Pr) 3 ] 2 for 3-furyl addition reactions of aromatic ketones; the reactions could be conducted at a mild temperature of 08C. 43 To further explore organoaluminum or organotitanium compounds as efficient nucleophiles for catalytic reactions, [44][45][46][47][48][49][50][51][52] we report herein the synthesis of three alkyltitanium compounds of RTi(O-i-Pr) 3 (R 5 Cy (1a), i-Bu (1b), and n-Bu (1c)). Asymmetric additions of 1a-1c to aromatic, heteroaromatic, or a,b-unsaturated aldehydes catalyzed by a titanium catalyst of (R)-H 8 -BINOL have been studied at room temperature, affording desired secondary alcohols in good to excellent enantioselectivities of up to 94% ee.…”