Reaktionen des 4-Bromo-1,6-methano[10]annulen-3-carbaldehyds: Synthese von 3,4-heteroanellierten 1,6-Methano[10]annulenen

Reactions of 4-Bromo-1,6-methano[10]annulene-3-carbaldehyde: Syntheses of 3,4-Heteroanellated 1,6-Methano[10]annulenes Similarly to β-chlorovinyl ketones, the title compound 1 reacts with dinucleophiles to give the 3,4-heteroanellated 1,6-methano[10]annulenes 2–4, 6 , and 12–16 , containing thiophene, pyrazole, pyrimidine, and thiazepine rings (Schemes 2 and 3). On reaction of 1 with tert-butylhydrazin, an unusual Michael-addition-dehydrogenation sequence, resulting in 2,3-anellation of a pyrazole ring (→ 5 ), is observed. Synthetic as well as some mechanistic aspects are briefly discussed.