Lithium cyclononatetraenide

Two laboratories - have reported the synthesis of isobullvaicne (7, tricyclo-[5.3.0.0 °]deca-3,5.,8-triene) in the same way from lithium cyclononatetraenide (6) by treatment with methylene chloride and n-butyllithium at a low temperature. The major product is isobullvalene (7), accompanied by the flOjannulene (8) and cij-9,10-... 

When lithium cyclononatetraenide is treated with iodine it is converted into a thermolabile, air-sensitive bis(cyclononatetraenyl) which reacts with potassium in tetrahydrofuran, in the absence of air and moisture, to give deep brown crystals of dipotassium bis(cyclononatetraenido) 182]. Addition of further potassium cleaves this dianion slowly to form potassium cyclononatetraenide ... 

Treatment of lithium cyclononatetraenide with bromomethyl acetate at low temperatures gives cyclonona-2,4,6,8-tetraen-l-yl methyl acetate, which reacts with potassium t-butoxide to give nonafulvene (289). ... 

Reaction of di- -propylboron chloride with lithium cyclononatetraenide followed by vacuum distillation afforded the mixture of boranes 23a,b, 43a and 44a,b in a 10 1 2 ratio (Scheme 2.28) [31,47]. The reaction was carried out in an NMR tube to elucidate the mechanism of formation of the unexpected product 23. Compounds 43a and 43b were the first observable products of the thermal rearrangement of cyclononatetraenyl(di-H-propyl)borane 22. Apparently, the... 

Acetoxymethyl-ds,trans,cis,trans-cyclonona-l,3,5,7-tetraene, prepared from lithium cyclononatetraenide and bromomethyl acetate at — 30 °C, was converted into 9-methylene-ci5,trans,cis,trans-cyclonona-l,3,5,7-tetraene by KOBuS Both 9-acetoxy-methyl- and 9-methylene-cyclononatetraenides were converted into the dihydro-indenes (222 R = CH2 H, CH2OAC) on warming. ... 

The cyclononatetraenide anion is generated by treatment of the halide 5 with lithium metal ... 

When 18 is treated with acetone, boronic ester 20 with a cyclooctatriene structure is cleanly obtained indicating the valence tautomerism between 18 and 19. In fact, 19 appears to be the kinetic product in the borylation of lithium or potassium cyclononatetraenide with alkylboron dihalides which rearranges quickly to 18 due to the comparatively high thermodynamic stability of the latter.1819 Acetaldehyde,... 

Both all-cis and mono-trans salts have been obtained as stable crystalline solids, but both are very sensitive to moisture and to oxygen. When lithium al 1-cjts-cyclononatetraenide was heated at 163° in an inert solvent for 30 hours more than 70% of the salt remained unchanged [66]. 

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