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

作者：Saitoh Hisashi; Ijuin Hisako K; Watanabe Nobuko; Matsumoto Masakatsu^*

来源：Helvetica Chimica Acta, 2013, 96(9): 1704-1713.

DOI：10.1002/hlca.201200653

• Cycloheptatrienyl anion
• Benzocycloheptene
• Cyclopropanaphthalene

When treated with (LiNPr2)-Pr-i (LDA) at -78 degrees, 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.

• 出版日期2013-9