1-Chloroethyl p-tolyl sulfoxid

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... 

Application of the method described above to unsymmetrical cyclic ketones such as 2-substituted cyclohexanones gave 2,7-disubstituted and 2,2,7-trisubstituted cycloheptanones (Scheme 8). Treatment of a-sulfinyl lithium carbanion of 1-chloroethyl p-tolyl sulfoxide with 2-substituted cyclohexanones (210a and 210b) afforded adducts as a mixture of two diastereomers. The main adducts were first treated with f-BuMgCl followed by i-PrMgCl (4 equiv) at 0°C to room temperature to give the magnesium /3-oxido carbenoid 211. The... 

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