Synthesis of Eleven-Membered Carbocycles via a Homo-Cope Type of Five-Carbon Ring Expansion Reaction Utilized β-(Hydroxymethyl)allylsilane.

ChemInform ◽  
2003 ◽  
Vol 34 (35) ◽  
Author(s):  
Hideyuki Suzuki ◽  
Chiaki Kuroda
Keyword(s):  
Ring Expansion ◽  
Carbon Ring ◽  
Ring Expansion Reaction

The formation of cycloheptenone and cycloheptadienones from bicyclo[3.2.0]heptanone derivatives. An acid-catalyzed, two carbon ring expansion reaction

1976 ◽  
Vol 54 (1) ◽  
pp. 12-18 ◽  
Author(s):  
Kenneth E. Hine ◽  
Ronald F. Childs
Keyword(s):  
Ring Expansion ◽  
Membered Ring ◽  
Acid Solutions ◽  
Ring Expansions ◽  
Carbon Ring ◽  
Ether Mixture ◽  
Synthetic Utility ◽  
Acid Catalyzed ◽  
Ring Expansion Reaction ◽  
Strong Acids

In strong acids, such as FSO3H and 96% H2SO4, bicyclo[3.2.0]heptan-6-one and bicyclo[3.2.0]hept-2-en-7-one undergo a clean isomerization to form protonated cyclohept-2-enone and cyclohepta-2,4-dienone, respectively. Substituted derivatives undergo comparable ring expansions when dissolved in these strong acids. The seven-membered ring ketones can be recovered on quenching the acid solutions with a NaHCO3–ether mixture. In contrast, bicyclo[3.2.0]hept-2-en-6-one when dissolved in FSO3H rearranged to give protonated 1-acetylcyclopentadiene. The mechanism and synthetic utility of these reactions is discussed.

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