Autoassembling of the quinuclidine nucleus: one-step synthesis, structure and properties of dimethyl 4-hydroxy-6,6,7,7-tetramethyl-Δ2-dehydroquinuclidine-2,3-di-carboxylate

Triacetonamine reacts with dimethyl acetylenedicarboxylate in MeOH to give an ordinary adduct, aminomaleate 2, while in aprotic solvents quinuclidine 1 is formed under mild conditions and in high yield; its structure is confirmed by spectroscopic methods as well as X-ray diffraction analysis. A mechanism of autoassembling is proposed, and chemical transformations of 1 with retention of quinuclidine nucleus are studied.