Cyclohexanones expansion with ethyl diazoacetate

Ring expansion (1, 369-370). Ring expansion of unsymmetrical a-mono-and a,a-disubstituted cyclopentanones and cyclohexanones (1) with ethyl diazoacetate in the presence of boron trifluoride etherate gives mixtures of (2) and... 

The one-carbon expansion of cyclohexanones with introduction of a carbonyl group, trifluromethyl, cyano, phosphonate or benzenesulfonate has also been reported to proceed in the presence of Lewis acids (Scheme 14). The analogous reactions of larger ring ketones [expressed as ring size (yield)] with ethyl diazoacetate [7 (81%), 8 (85%)] and phenylsulfonyldiazomethane [7 (86%), 8 (27%), 12 (43%), 14 (48%), 15 (54%) and 16 (58%)] have also been reported. In the reaction of ethyl diazoacetate and... 

Related to simple chain extension is ring expansion and contraction useful because some ring sizes are easier to make than others. So available cyclohexanone can be expanded into cycloheptanones such as the useful keto-ester 20 with an activated position for enolate reactions. The reagent is ethyl diazoacetate 18 readily available from glycine esters. Addition to the ketone 18 automatically... 

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