Fulvenes, formylation

This procedure illustrates formylation by N,N-dimethylamino-methoxymethylium methyl sulfate, a compound which can be produced readily by reaction of easily available materials. 6-(Dimethylamino)fulvene is a useful intermediate for the synthesis of various f used-ring nonbenzenoid aromatic compounds. 

The timescale of a microwave observation is ca 10 12s so that an average of the properties of the species in equilibrium (35) is obtained if the equilibrium occurs in a time shorter than this. The X-ray photoelectron spectra of intramolecularly hydrogen-bonded species in the gas phase have been studied in an attempt to obtain an instantaneous picture of the structure of these molecules. In this technique the ionisation of core electrons which occurs within 10 16s is observed. For malondialdehyde, 6-hydroxy-2-formyl-fulvene, 2-hydroxy-1,1,1,5,5,5-hexafluoropent-2-ene-4-one, 9-hydroxyphen-alenone [19], and tropolone [20], two peaks are observed in the Ou region of the photoelectron spectrum (Brown et al., 1979). If these molecules existed in the C2v form with a symmetrical hydrogen bond and equivalent oxygen... 

Durch Umsetzung von 6-Dimethylamino-(2-nitro-ethenyl)-fulven mit Propinal bzw. 3-Oxo-l-butin in Benzol unter RuckfluB erhalt man durch Cyclokondensation 7-Formyl-5-nitro- bzw. 7-Acetyl-5-nitroazulen in 35 bzw. 52%iger Ausbeute3 ... 

The formation of fulvene (450) by sodium borohydride reduction of 2-formyl-4//-pyran (371) in water347 may be explained by the mechanism shown in Scheme 21. 

The formylation of styrene derivatives has been extended to several related alkene derivatives indene (52) gives 2-formylindene (53 20%), polyenes (54) and (55) afford aldehydes (56 92%) and (57 29-65%), and fulvene derivative (58) yields (59). In several cases, the products of monosubstitution described above are accompanied by products of polysubstitution, particularly under forcing conditions. For example, 2-phenylpropene reacts with salt (1) to give 4-phenylpyridine-3-carbaldehyde (60) after treatment with aqueous ammonium chloride solution. A useful synthesis of biphenyls (61 30-98%) from alcohol derivatives (62) and salt (1) has recently been reported. ... 

Monoformylation of 6-(dimethylamino)fulvene followed by hydrolysis gives 2-formyl-6-hydroxyfulvene [73] ... 

With these reagents the presence of an amine substituent on the 6-carbon atom markedly facilitates bromination [246]. This is an example of the way in which 6-amino groups activate the cyclopenta-diene ring to electrophilic attack these fulvenes can be regarded as enamines. Another example is provided by the ready formylation... 

---