Site-Selective Pyridyl Alkyl Ketone Synthesis from N-Alkenoxypyridiniums through Boekelheide-Type Rearrangements
Qiang Liu1,2, Chao-Shen Zhang1, He Sheng1
1School of Chemical Sciences, University of the Chinese Academy of Sciences, Beijing 100049, China.
Abstract:
The Boekelheide rearrangement is often employed for the oxy-functionalization of alkyl groups in the 2-position of pyridines, yet the corresponding alkylation reaction has so far not been realized since 1954. N-Alkenoxypyridinium functionalization has been widely applied to synthesize various carbonyl compounds by only using the carbonyl unit. Herein, we describe a simple yet efficient alkylation of N-alkenoxypyridiniums through the Boekelheide reaction for the synthesis of β-2-pyridyl alkyl ketones.
Related Concept Videos
α-Alkylation of Ketones via Enolate Ions
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.
Aldol Condensation with β-Diesters: Knoevenagel Condensation
Synthesis of α-Substituted Carbonyl Compounds: The Stork Enamine Reaction
Preparation of Alkynes: Alkylation Reaction
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.
Preparation of Aldehydes and Ketones from Alcohols, Alkenes, and Alkynes


