Novel Intramolecular Cyclization of 2‐(Buta‐1,3‐dienyl)benzyl Anions to 6,7(9)‐Dihydro‐5H‐benzocycloheptenyl Anions Leading to Successive Formation of 1,2‐Dihydrocyclopropa[a]naphthalenes |
| |
| Authors: | Hisashi Saitoh Hisako K Ijuin Nobuko Watanabe Masakatsu Matsumoto |
| |
| Institution: | 1. Department of Chemistry, Kanagawa University, Tsuchiya, Hiratsuka, Kanagawa 259‐1293, Japan, (phone: +81‐463‐59‐4111;2. fax: +81‐463‐58‐9684) |
| |
| Abstract: | When treated with LiNiPr2 (LDA) at ?78°, 1‐(methylsulfanyl)methyl]‐2‐(1Z,3E)‐4‐phenylbuta‐1,3‐dien‐1‐yl]benzene easily cyclized to form benzocycloheptenyl anion, which successively underwent intramolecular nucleophilic substitution to give a cyclopropanaphthalene. Similar LDA‐mediated cyclization also occurred for 4‐phenyl‐ or 4‐methyl‐substituted 1‐2‐(methoxymethyl)phenyl]buta‐1,3‐dienes to furnish the corresponding benzocycloheptenes and cyclopropanaphthalenes. A 4‐tert‐butyl analog also underwent LDA‐mediated cyclization to give a benzocycloheptene, but not a cyclopropanaphthalene. |
| |
| Keywords: | Cycloheptatrienyl anion Benzocycloheptene Cyclopropanaphthalene |
|
|
