1.2- Cyclohexanedione rearrangement

Thus, a-sulfinyl lithium carbanion of 1-chloroethyl p-tolyl sulfoxide was reacted with 1,4-cyclohexanedione mono ethylene ketal (195) to afford the adduct (196) in quantitative yield. The adduct was treated with ferf-butylmagnesium chloride (magnesium alkoxide was initially formed) followed by isopropylmagnesium chloride to result in the formation of magnesium /3-oxido carbenoid 197. The /3-oxido carbenoid rearrangement then takes place to give one-carbon expanded magnesium enolate 198. Finally, an electrophile was... 

Rearrangement ofl,2-dialkyl- y3-cyclohexanediones.1 Reaction of these substrates with the anion (LDA) of this phosphonate results in rearrangement to 3-alkyl-2-cyclohexenones in 60-93% yield. Addition of ClSi(CH3)3 improves the yield. The... 

Addition of secondary and tertiary enaminones derived from 1,2-cyclohexanediones as dienophiles to acetylbenzoquinone leads in a hetero-Diels-Alder reaction to benzo[c]-chromentriones. The Diels-Alder adducts are unstable and rearrange easily to condensed benzofurans. They can be converted by acids to a carbazolone derivative in low yield and to cyclopenta- and cyclohexa[c]isoquinolinium salts in fair yield32 (equation 246). 

Epoxides of a,p-unsaturated ketones can undergo a ring opening/arylation reaction under Heck conditions <05JOC4720>. Epoxide 62 undergoes an initial Pd-catalyzed rearrangement to a 1,2-cyclohexanedione which then undergoes a Heck arylation reaction to... 

Aliphatic diketones rearrange similarly. Thus, 1,2-cyclohexanedione is converted to 1-hydroxy-l-cyclopentanecarboxylic acid (Equation 9.70). 

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