Raise the anchor! Synthesis, X-ray and NMR characterization of 1,3,5-triazinanes with an axial tert-butyl group

ZATYKINA, ANASTASYA D; GRIGORIEV, MIKHAIL; NOVIKOV, ROMAN A; GRUDOVA, MARIYA V; ZAYTSEV, VLADIMIR P.; ZUBKOV, FEDOR IVANOVICH; KLETSKOV, ALEXEY V; SINELSHCHIKOVA, ANNA A; GIL, DIEGO M.; FRONTERA, ANTONIO

ORGANIC & BIOMOLECULAR CHEMISTRY

ROYAL SOC CHEMISTRY

Año: 2020 vol. 18 p. 8386 - 8394

1477-0520

N-t-Bu-N?,N??-disulfonamide-1,3,5-triazinanes were synthesized and characterized by X-ray single crystal structure analysis. In the course of the X-ray structure elucidation, the first solid experimental evidence of the axial position of the tert-butyl group in unconstrained hexahydro-1,3,5-triazacyclohexanes was obtained. Dynamic low-temperature NMR analysis allowed to fully investigate a rare case of crystallization-driven unanchoring of the tert-butyl group in the chair conformation of saturated six-membered cycles. DFT calculations show that the utilization of explicit solvent molecules is necessary to explain the equatorial position of the t-Bu group is solution. Otherwise, the axial conformer is the thermodynamically stable isomer.