Construction of the 1,5-methano[10]annulene (bicyclo[5.3.1]-undeca-1,3,5,7,9-pentaene) system

Excited States of 1,6-Methano[10]annulene: Site Selection Fluorescence and Fluorescence Excitation Spectroscopy on S1

“…For steric reasons (ring strain or, in the case of the trans-trans isomer, crowding of the inner hydrogen atoms) all of these annulenes exist in nonplanar conformations and are thus olefinic. To arrive at planar or nearplanar 10-membered rings, two concepts have been applied: (1) replacement of 1,6-or 1,5-positioned hydrogen atoms of [10]annulenes by a CH 2 group affording bridged [10]annulenes [20][21][22][23][24][25][26] and (2) introduction of two triple bonds to give 1,6-didehydro [10]annulene. 27 Research on [10]annulenes has focused on 1,6-methano [10]annulene, 1 (see Figure 1), since it is accessible fairly readily, possesses a near-planar C 10perimeter, and is a stable aromatic molecule.…”

Facets of the Tetsuo Nozoe Legacy Immortalized in an Enduring Series of International Symposia on Novel Aromatic Compounds (ISNA)

“…Twenty minutes had been allotted for my talk right before lunch on Tuesday. My anxiety was heightened further by the fact that Satoru Masamune, a member of the Nozoe School, who was by then an eminent professor himself at MIT, had just published syntheses of the first derivatives of this previously unknown ring system, and I knew that he would be in the audience, too. He had been a plenary lecturer at ISNA‐2 and had returned to ISNA‐3 as a member of the scientific organizing committee and as a session chair.…”

Fluorescence excitation and UV–UV double-resonance spectroscopy of the S0 → S1(Lb) transition of 1,6-methano[10]annulene cooled in a supersonic jetDedicated to Professor F. Dörr on the occasion of his 80th birthday.

“…11 Subsequently other [10]-, [14]-, [18]-, and [22]-annulenes were synthesized which are in a similar fashion related to azulene, anthracene, phenanthrene, tetracene, and pentacene. [12][13][14][15][16] The first aromatic C n H n -annulene without bridges was [18]annulene synthesized by the group of Sondheimer. 17 This compound can assume a planar conformation of D 6h symmetry which is free of strain.…”