Cyclohept-4-enone derivative

Sol 10. (i) The l-alkenyl-4-pentyn-l-ol system (I) undergoes a microwave-assisted tandem oxyanionic 5-exo-dig addition reaction/Claisen rearrangement sequence to give cyclohept-4-enone derivative (II). 

Alkoxyalk -6-en-l-ynes undergo cyclization to give cyclohepta-l,4-diene derivatives. The analogous siloxy enynes provide cyclohept-4-enones as major products. However, a change of the phosphine ligand to a more electron-rich version diverts the reaction pathway to the formation of products of a different type. ... 

A similar photoreaction of the MBH adduct derived from cyclohept-2-enone gives 1,4-diketones 398 and 399 without ring contraction, whereas the MBH adduct obtained from y,y-disubstituted cyclohex-2-enone gives 1,4-diketones... 

Lithiated bis(methylthio)(trimethylsilyl)methane undergoes a Michael addition with cyclohept-2-enone to give (309) after hydrolysis. 4-Chloro-2,6-bis(methylthio) thiopyrylium perchlorate condenses with P-diketones in the presence of triethylamine to give thiopyranylidene derivatives, e.g. cycloheptane-1,3-dione gave (310). ... 

Bicyclo[3,2,0]heptan-6-ones and bicyclo[3,2,0]hept-2-en-7-ones are cleanly iso-merized to cyclohept-2-enones and cyclohepta-2,4-dienones, respectively, in strong acids such as FSO3H and 96% H2SO4, e.g. (174) -> (175), and a useful method of converting phenols into cycloheptane derivatives of type (176) is by flash vacuum pyrolysis of their propiolate esters. Mixtures of isomeric cycloheptadienols are produced when the epoxide resulting from addition of dimethylsulphonium methyl-ide to acylvinyIcyclopropane is heated at 180 °C for 12 h. ... 

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