Stereodirected reactions of salicilaldehyde derivatives with tert-butyl 3(4)-hydroxy-2(3)-(3-methylbut-2-enyl)- piperidine-1-carboxylates as an efficient preparation procedure of tetrahydropyran derivatives fused with a piperidine ring

Abstract

Reaction of salicilaldehyde and its derivatives with unsaturated cis-, trans-alcohols of the piperidine series in the presence of methyl orthoformate and p-toluenesulfonic acid led to the formation of a new heterocyclic system connecting four fuzed rings (two tetrahydropyrans, a piperidine, and an aromatic ring), 6,6-dimethyl-6а,7,7а,8(9),10,11,11а,12а-octahydrochromeno[3′,4′:5,6]pyranо[3,2-с(b)]pyridine.