3,5-Bis(ferrocenylmethylene)-1-methyl-4-methylenepiperidine. Synthesis and some chemical properties

Cross-conjugated 3-ferrocenylmethylidene-2,4-dimethylpenta-1,4-diene in cationic cycloaddition and proton-catalyzed cyclodimerization reactions

“…To date, syntheses of 3-ferrocenylmethylidene-2-methylidenecamphane (2a) [5,6], 2-ferroicenylmethylidene-3-methylidenequinuclidine (2b) [7] 1,3-bisferrocenylmethylidene-2-methylidenecyclohexane (2c) and cycloheptane (2d) [8,9], and 3,5-bisferrocenylmethylidene-4-methylidene-1-methylpiperidine (2e) [10] (Scheme 2) have been carried out and their chemical properties have been studied.…”

“…The chemical behavior of compounds 2a-e has been examined in the following reactions: cycloaddition, dimerization, and cyclodimerization (thermal, proton-catalyzed, and cation-catalyzed) [5][6][7][8][9][10], which occurred highly diastereoselectively. The stepwise non-synchronous mechanism of proton/cation-catalyzed cyclodimerization has been proven experimentally, this reaction afforded fused polycarbo (or -hetero) cycles of unusual structures with spiro-or ''three-petal''-type of fusion [11].…”