Metal- and CO-Free Carbonylation of Alkyl Iodides
Emilien Le Saux1, Maurus Mathis1, Giorgia Panizzolo1
1Laboratorium für Organische Chemie, ETH Zürich, 8093 Zürich, Switzerland.
Abstract:
We report a new method for the carbonylation of alkyl iodides under photochemical conditions. The process relies on a simple aryl formate reagent, synthesized in one step from readily available chemicals and capable of releasing CO along with a phenolate species in the presence of a mild base. The photoactivity of this phenolate is harnessed to activate alkyl iodides via single-electron transfer and generate alkyl radicals that add to CO and ultimately offer access to carboxylic acids and amides. This new, user-friendly procedure overcomes the typical need for CO gas and/or metal catalysts in carbonylation chemistry while being highly efficient and versatile to accommodate a variety of functional groups.
Related Concept Videos
Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Alkenes via Reductive Coupling of Aldehydes or Ketones: McMurry Reaction
Halogenation of Alkenes
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
Acid Halides to Alcohols: Grignard Reaction
Grignard reagents are a source of carbanions and function as nucleophiles. The mechanism begins with the nucleophilic attack by the carbanion at the carbonyl carbon of the acid halide to form a tetrahedral intermediate. Next, the carbonyl group is re-formed, and the halide ion departs,...
Carbocations


