Development of a Catalytic Platform for Nucleophilic Substitution: Cyclopropenone‐Catalyzed Chlorodehydration of Alcohols

Oxalyl Chloride: A Versatile Reagent in Organic Transformations

“…60 years ago and for the first time, the synthesis of cyclopropenones was reported by two research teams led by Breslow and Volpin, independently. In 2011, Lambert and Vanos employed cyclopropenone as a catalyst in the asymmetric conversion of alcohols 13 to the corresponding alkyl chlorides 14 using oxalyl chloride as a chlorinating reagent at room temperature via second‐order nucleophilic substitution (SN 2 ) (Scheme ) …”

“…One of the most important characteristics of oxalyl chloride is its usefulness as a chlorinating reagent of various functional groups . It can convert the alcohols to alkyl halides without or with aim of several catalysts including TPPO, DMF, DMSO, and cyclopropenone, depending on kind of alcohol and some other parameters. Combination of oxalyl chloride with DMF forms Vilsmeier reagent [(Me 2 N=CHCl + )Cl − ] which can be used for formylation, which oxalyl chloride could not do it, solely .…”

Promotion of Organic Reactions by Non‐Benzenoid Carbocyclic Aromatic Ions

“…[42] They proposed ac atalytic cycle (Scheme 16) in which cyclopropenone 94 would favorably react with an activating agent such as oxalyl chloride to produce the cyclopropenium salt 130.T he salt subsequently coupled with the alcohol substrate 127 to generate the cyclopropeniumactivated intermediate 128.Nucleophilic displacement by the counterion of 128,o ro ther nucleophiles present in the reaction mixture,w ould produce the substituted target product 129 and regenerate cyclopropenone 94.V anos and Lambert investigated the formation of products in which the cyclopropenone ring had different electronic and steric characteristics.A ne xploration of alternative groups showed that large aryl substituents had little influence,w hereas electron-withdrawing groups had adverse effects on product formation. [42] They proposed ac atalytic cycle (Scheme 16) in which cyclopropenone 94 would favorably react with an activating agent such as oxalyl chloride to produce the cyclopropenium salt 130.T he salt subsequently coupled with the alcohol substrate 127 to generate the cyclopropeniumactivated intermediate 128.Nucleophilic displacement by the counterion of 128,o ro ther nucleophiles present in the reaction mixture,w ould produce the substituted target product 129 and regenerate cyclopropenone 94.V anos and Lambert investigated the formation of products in which the cyclopropenone ring had different electronic and steric characteristics.A ne xploration of alternative groups showed that large aryl substituents had little influence,w hereas electron-withdrawing groups had adverse effects on product formation.…”

Nucleophilic Aliphatic Substitution

“…130 Product studies suggest that oxalyl chloride converts the cyclopropenone into chloride ion and a 1-chloro-2,3-di(p-methoxyphenyl)cyclopropenyl carbenium ion, which reacts with the alcohol at C(1) of the carbenium ion. Loss of the alcohol proton gives 1-chloro-2,3-di(p-methoxyphenyl)cyclopropenyl ether.…”