Some generalizations concerning the reactivity of aryl positions adjacent to fused strained rings

The reaction of sulfur with dilithio compounds. The syntheses and structures of phenanthro [1, 10‐cd]‐1,2‐dithiole and phenanthro[4,5‐cde] [1,2]dithiin

“…Under the same conditions as above, 1 gives a 1 :2 mixture of thiophene 3 and triphenyleno-[1, 12- Since phenanthrene (9) has both bay (C,, C,) and peri (C9, Clo, C1, CJ positions, polylithiation is potentially more complicated [ 1,2]. In fact, prior deuterium exchange experiments indicate that both regions are dilithiated [2,9]. Treatment of 9 with butyllithium/TMEDA followed by s 8 gives a mixture of 45% dithiin 10,30% thiophene 13, and 25% dithiole 11.…”

“…This sequence allows simultaneous detection of 1,3-and 1,4-dilithiation. In this manner, phenanthrene (9) has been converted to 10 and 11. The crystal and molecular structures of these novel heterocycles have been determined.…”

“…It is likely that bay and peri positions are most acidic, since they are adjacent to the ring fusion [9]. The dilithio products are then formed by the selective lithium directed lithiation to the adjacent peri or bay position to give 14 or 15.…”

In Search of Simplicity and Flexibility: A Rational Access to Twelve Fluoroindolecarboxylic Acids

“…The combination of the two effects increases, for example the statistically corrected kinetic acidity of biphenylene, relative to that of benzene, at the 2-position by a factor of 6.2 but at the 1-position by a factor of 490. [55][56][57] σ/π-Polarization presumably acts as an additional acidity-enhancing effect. N-Acyl-or N-nitroso-N-methylamines readily undergo lithiation of the methyl group.…”

Synthese des Kohlenstoffoxids C12O6 über hoch gespannte Benz‐ine

“…Die Autoren führen sie vielmehr auf den anellierten [21,22] Als Konsequenz ist das sp-hybridisierte Kohlenstoffatom, das dem anellierten Ring benachbart ist, wegen des erhöhten sCharakters an ein Orbital größerer Elektronegativität gebunden. Dies führt dazu, dass das andere sp-Kohlenstoffatom elektronenärmer wird.…”