Iron(II)-catalyzed oxidative coupling of vicinal diols and 2-amino- 1,4-naphthoquinone for the synthesis of pyrrolonaphthoquinones and furanonaphthoquinones Sujit Maity, Sandip Kumar Gupta, Prof. Dr. Niranjan Panda Direct oxidative coupling of a vicinal diol with 2-aminonaphthoquinones has been studied for the selective synthesis of benzo[ f ]indole-4,9-diones at a moderate temperature 1 . In the presence of an environmentally benign iron catalyst, the vicinal diols were oxidized to α-hydroxy carbonyl compounds 2 . Subsequently, 2-aminonaphthoquinone reacted with the resultant α-hydroxy carbonyl compound through tandem N-C and C-C bond formation to afford a vast range of pyrrolonaphthoquinones in remarkable yield. Interestingly, when the 1,2-propanediol was used, the secondary alcohol group was oxidized preferably by resulting in the 2-methyl pyrrolonaphthoquinones as the major regioisomer. The synthetic utility of the current strategy was extended for one-step delivery of natural products, such as 3-methyl-1 H -benzo[ f ]indole-4,9-dione (a secondary metabolite isolated from Goniothalamus tapis Mq. with anti-PAF activity), antibiotic utahmycin B (3-methyl-1 H -benzo[ f ] indole-4,9-dione), cytotoxic avicequinone B and anti-viral FNQ3 (2-methyl-naphtho- [2,3- b ]furan-4,9-dione).
References 1. Maity, S.; Gupta, S. K.; Panda, N. Asin J. Org. Chem. 2021 , 10 , 3355–3363. 2. Panda, N.; Jena, A. K. J. Org. Chem. 2012 , 77 , 9401.
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