Thermodynamic α-CH acidities of amino acid fragments in five-co-ordinate bicycloazastannoxides in Me2SO

Abstract

The thermodynamic α-CH acidities of the amino acid moieties in six five-co-ordinate bicycloazastannoxides in Me₂SO have been studied. Their pK_a values are in the range 17.40–18.50. The effects of the bulkiness of the amino acid moieties and the central metal atom (Sn) on the thermodynamic α-CH acidity are interpreted. The crystal structure of one complex was determined, and the formation of its α-carbanion intermediate under the action of 0.1 mol dm^–3 NaOCD₃ has been confirmed by ¹H NMR spectrometry.