title: Mild Aliphatic and Benzylic Hydrocarbon C-H Bond Chlorination Using Trichloroisocyanuric Acid.
abstract: We present the controlled monochlorination of aliphatic and benzylic hydrocarbons with only 1 equiv of substrate at 25-30 °C using N-hydroxyphthalimide (NHPI) as radical initiator and commercially available trichloroisocyanuric acid (TCCA) as the chlorine source. Catalytic amounts of CBr4reduced the reaction times considerably due to the formation of chain-carrying ·CBr3radicals. Benzylic C-H chlorination affords moderate to good yields for arenes carrying electron-withdrawing (50-85%) or weakly electron-donating groups (31-73%); cyclic aliphatic substrates provide low yields (24-38%). The products could be synthesized on a gram scale followed by simple purification via distillation. We report the first direct side-chain chlorination of 3-methylbenzoate affording methyl 3-(chloromethyl)benzoate, which is an important building block for the synthesis of vasodilator taprostene.
authors.affiliation: Institute of Organic Chemistry, Justus-Liebig University , Heinrich-Buff-Ring 17, 35392 Giessen, Germany.
authors.forename: Sascha H
authors.initials: SH
authors.lastname: Combe
authors.affiliation: Institute of Organic Chemistry, Justus-Liebig University , Heinrich-Buff-Ring 17, 35392 Giessen, Germany.
authors.forename: Abolfazl
authors.initials: A
authors.lastname: Hosseini
authors.affiliation: Departamento de Química Orgánica, Universidad Autónoma de Madrid Cantoblanco , 28049 Madrid, Spain.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Parra
authors.affiliation: Institute of Organic Chemistry, Justus-Liebig University , Heinrich-Buff-Ring 17, 35392 Giessen, Germany.
authors.forename: Peter R
authors.identifier: 0000-0002-3608-5515
authors.initials: PR
authors.lastname: Schreiner
mesh_terms: D066241:Carbon-13 Magnetic Resonance Spectroscopy; D002713:Chlorine / Q000737:chemistry*; D006838:Hydrocarbons / Q000737:chemistry*; D066244:Proton Magnetic Resonance Spectroscopy; D014227:Triazines / Q000737:chemistry*
chemical_list: D006838:Hydrocarbons; D014227:Triazines; C557580:trichloroisocyanuric acid; D002713:Chlorine