Cycloalkanones ring contraction

Reduction, carboxyl groups, 56,83 Reduction of a,0-unsaturated p-toluene-sulfonyl-hydrazones to alkenes, 59,42 Reductive alkylation, 56,52 Reductive cleavage, 56, 101 Resolution of amines, 55,80, 83 Rexyn 201,55,4 Rhodium(III) oxide, 57, 1 Ring contraction, 56, 107 Ring expansion of cycloalkanones to cycloalkenones, 59, 113... 

King enlargement of cycioalktmones.2 A novel method for homologation of cycloalkanones (1) to ot-benzylsulfonylcycloalkanones (2) is shown in equation (I). The products can be converted into 1-benzylsulfonyl-l -cycloalkcnes (4) by ring contraction. 

Cycloalkanones of ring size from four to six oxidize with ring contraction to give the cycloalkanecar-boxylic acid of the next smaller ring size with thallium(III), as shown in equation (44). This reaction... 

Ring contraction (7, 138). Details for the conversion of cyclododecanone (1) to cycloundecanecarboxylic acid (2) with this reagent are available. With six- to eight-membered cycloalkanones the overall yields are about 75%. In the case of cyclohexadecanone the overall yield is 68%.2... 

Hydroxymercuration and thallium(III) oxidation of cycloalkenes, 1-methylcycloalkenes and methylenecycloalkanes have been reported to yield ring-contracted aldehydes, ring-contracted ketones and ring-expanded cycloalkanones, respectively. 

Lessard, Spino, and coworkers developed the formation of iV-heterocycles from cycloalkanones using a photochemical ring contraction reaction coupled with a Beckmann rearrangement ring expansion." Their methodology is an impressive approach to transform disubstituted cycloalkanones into N-heterocycles of the same ring size tSchemp The... 

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