Diastereo- and regioselective petasis aryl and allyl boration of ninhydrins towards synthesis of functionalized indene-diones and dihydrobenzoindeno-oxazin-ones.

Ayon Sengupta, Suvendu Maity, Pinaki Saha, Prasanta Ghosh, Sonali Rudra, Chhanda Mukhopadhyay

Molecular diversity 2023 Jun

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Petasis aryl and allyl borations were accomplished using substituted ninhydrins, boronic acids or 2-allyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane and 1,2-aminophenols in Hexafluoroisopropanol (HFIP) without any catalysts to synthesize different aryl and allyl derivatives of ninhydrins. The nature of substitution in the boronic acids and 1,2-amino phenols was the key factor in determining the diastereo-regioselectivity and the type of product distributions. The products were isolated and characterized by HMBC, HSQC, 1H, 13C NMR experiments and X-ray single crystallographic analysis. A probable reaction pathway involves in situ formation of acyclic and cyclic ninhydrin-amino alcohol adducts, with the positioned hydroxyl group determining the stereo-regioselective outcome via tetracoordinated boron intermediates. A metal free diastereo- and regioselective Petasis aryl and allyl boration of ninhydrins. © 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.

Citation

Ayon Sengupta, Suvendu Maity, Pinaki Saha, Prasanta Ghosh, Sonali Rudra, Chhanda Mukhopadhyay. Diastereo- and regioselective petasis aryl and allyl boration of ninhydrins towards synthesis of functionalized indene-diones and dihydrobenzoindeno-oxazin-ones. Molecular diversity. 2023 Jun;27(3):1385-1400