Radical Carboaminoxylation with Subsequent Pd-Catalyzed Intramolecular Allylation for the Construction of Five- and Six-Membered Carbocycles

Abstract

Regioselective intermolecular radical carboaminoxylation using various alkoxyamines are presented. These environmentally benign tin-free radical additions can either be performed under microwave conditions at 180 °C or by using conventional heating at 125 °C. Intermolecular Trost-Tsuji allylation of the carboaminoxylation products provide five- and six-membered carbocycles in moderate to good yields. The radical addition/Pd-catalyzed intramolecular allylation can be performed as one-pot process.

Key words

radical chemistry - nitroxides - allylations - Pd catalysis

References

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13

Diene 1d turned out to be unstable under the reaction conditions.

14

Compounds 5a-d were isolated as 1:1 mixture of diastereoisomers. The isomers could not be separated. For 6a-c all four isomers (ratio 1:1:1:1) were formed. These isomers could not be separated.

17

The isomers could not be separated. Due to the complexity of the NMR spectra, the determination of the diastereoisomeric ratio for compounds 9a and 9c was not possible. For 9b the product was formed as a 30:12:3:1 mixture of isomers.