Tert BUTYLCYANOKETENE

The submitters have not been successful in isolating tert-butylcyanoketene by any method. If the solvent is removed, the ketene polymerizes. The spectral properties of the product are as follows infrared (benzene) cm.-1 2220 (C=N), 2130 (C=C=0) proton magnetic resonance (benzene) <5, multiplicity, assignment 0,75 [singlet, C(CH3)3],... 

Typical reactions of tert-butylcyanoketene are shown in the chart. 

Diazido-3,6-di-tert-butyl-l,4-benzoquinone refluxed 45 min. in anhydrous benzene tert-butylcyanoketene. Y almost 100%. - The product is a surprisingly stable yet very reactive ketene. F. e. and reactions of the product s. H. W. Moore and W. Weyler, Jr., Am. Soc. 92, 4132 (1970). 

HCl-gas passed 0.5 hr. through an ice-cooled soln. of tert-butylcyanoketene in benzene, excess HCl removed by a stream of Ng, stirred and treated dropwise at 0° with triethylamine l,3-di-ter/-butyl-l,3-dicyanoallene. Y 95%. H. W. Moore and W. G. Duncan, J. Org. Chem. 38, 156 (1973). 

F. tert-Butyhyanoketene. Tj-pically the ketene is prepared by dissolving 1 g. of 2,5-diazido-3,6-di-starting material as well as the intermediate cyclopentenedione is followed by thin layer chromatography v(Note 17). When the cyclopentenedione is no longer detectable, after approximately 90 minutes, the heating is stopped. The solution contains ferf-butylcyanoketene in amounts equivalent to at least a 95% yield (Note 18). 

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