Stereoselectivity of formation of polycyclic ferrocenyl-4,5-dihydropyrazoles based on E- and Z-s-cis-alpha,beta-enones

Reaction of E- and Z-isomeric 2-ferrocenylmethylidene-1-tetralone, 2-ferroc enylmethylidene-3-quinuclidinone 1-methyl-3-ferrocenylmethylidene-4-piperid one and 2-ferrocenylmethylidenetropinone with hydrazine proceeds stereospec ifically with the-formation of the same diastereomeric polycyclic ferroceny ldihydropyrazoles independently of the geometric configuration of the start ing alpha,beta -unsaturated ketones. X-ray structural analysis is presented for the trans-diastereomer of 4-acetyl-3-ferrocenyl-1,4,5-triazatricyclo[5 .2.2.0(2,6)]undec-5-ene. (C) 2001 Elsevier Science B.V. All rights reserved .