Existing in the structure of many biologically active natural products, 2-oxindole skeleton, especially with spirocycles, has attracted the interest of researchers in the fields of synthetic organic and medicinal chemistry. Therefore, chiral 3-substituted-2-oxindole compounds are widely utilized as precursor for the synthesis of 2-oxindole fused heterocycles and cycloalkyl compounds. Among these, chiral amines obtained by direct nucleophilic addition to isatin (2,3-indolinedione) have potential for being transformed into above mentioned heterocycles. In this study, asymmetric organocatalytic addition of carbanions generated by the base-promoted deprotonation of α-azido ketones with isatin derived ketimines was aimed. In the presence of bifunctional quinine-derived 2-adamantyl substituted squaramide catalyst, corresponding 3-amino-3-(1-azido)indolin-2-one derivatives were synthesized with good diastereoselectivities (dr: 84:16 - 96:4) and high enantioselectivities up to 96% ee. Resulting azido adducts are also valuable synthons for 1,3 dipolar azide-alkyne cycloaddition reactions. In this regard, synthesis of various 1,2,3-tirazoles from chiral 3-amino-3-(1-azido)indolin-2-ones were also investigated.

Asymmetric organocatalytic addition of α-azido ketones to isatin-derived ketimines

255th National Meeting (2018)

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