Migratory selectivity in the ring expansion of .alpha.,.beta.-unsaturated cyclic ketones via .beta.-hydroxy selenides

1985 ◽  
Vol 50 (25) ◽  
pp. 5200-5204 ◽  
Author(s):  
Leo A. Paquette ◽  
John R. Peterson ◽  
Robert J. Ross
Keyword(s):  
Ring Expansion ◽  
Cyclic Ketones ◽  
Alpha Beta

α-Diazoacetamides in Sc(OTf)3-Catalyzed Tiffeneau–Demjanov Ring Expansion: Application towards the Synthesis of Rare Bicyclic Pyrazoles

Synlett ◽  
2020 ◽  
Vol 31 (04) ◽  
pp. 373-377
Author(s):  
Mikhail Krasavin ◽  
Sergey Chuprun ◽  
Dmitry Dar’in ◽  
Grigory Kantin ◽  
Petr Zhmurov
Keyword(s):  
Ring Expansion ◽  
Cyclic Ketones ◽  
Lawesson’S Reagent ◽  
Lawesson's Reagent

A novel Sc(OTf)3-catalyzed Tiffeneau–Demjanov ring expansion of six-membered cyclic ketones has been developed. The resulting seven-membered cyclic β-keto carboxamides were found to be versatile precursors to rare bicyclic pyrazoles obtained in modest to good yields via condensation with aryl hydrazines in the presence of Lawesson’s reagent.

Carbenoid type base induced ring expansion of the adducts of cyclic ketones with bis(phenylthio)methyllithium

1987 ◽  
Vol 28 (20) ◽  
pp. 2203-2206 ◽  
Author(s):  
William D. Abraham ◽  
M. Bhupathy ◽  
Theodore Cohen
Keyword(s):  
Ring Expansion ◽  
Cyclic Ketones

The Use of α-Diazo-γ-butyrolactams in the Büchner–Curtius–Schlotterbeck Reaction of Cyclic Ketones Opens New Entry to Spirocyclic Pyrrolidones

Synlett ◽  
2020 ◽  
Vol 31 (10) ◽  
pp. 982-986 ◽  
Author(s):  
Mikhail Krasavin ◽  
Maria Eremeyeva ◽  
Daniil Zhukovsky ◽  
Dmitry Dar’in
Keyword(s):  
Drug Design ◽  
Ring Expansion ◽  
Cyclic Ketones ◽  
Ring Expansions ◽  
Recent Success ◽  
New Entry

The only cyclic α-diazocarbonyl compound employed in the Büchner–Curtius–Schlotterbeck ring expansion of cyclic ketones to date was α-diazo-γ-butyrolactone. Encouraged by the recent success using α-diazo acetamides in related Tiffeneau–Demjanov type ring expansions, we extended this approach to various α-diazo-γ-butyrolactams, which produced, under BF3·OEt2-promoted conditions, spirocyclic seven-membered ketones. These findings substantially enhance the possibilities offered by cyclic α-diazocarbonyl compounds in constructing privileged spirocyclic scaffolds for drug design.

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