Carbamates tert-butoxide

Crotonaldehyde and its congeners are easily and often stereospecifically converted to trans-butadienyl carbonates and carbamates by treatment with potassium tert.butoxide... 

Of interest, it was possible to effect protecting group exchange from the benzyl or phenyl carbamate to the tert-butyl derivative by exposure of this material to potassium tert-butoxide in... 

Development of xanthate and dithiocarhamate derivatives overcomes several drawbacks of the sulfonium monomer (Scheme 7.2b and c). Xanthates and dithiocarbamates are easily prepared by the reaction of bis(halomethyl)benzene with alkylxanthate and dialkyldithiocarbamate salts respectively. Both precursors are stable at room temperature and soluble in organic solvents. This means the polymerization of these monomers can be performed in organic solvents e.g. THE) with the addition of alkoxide base e.g. potassium tert-butoxide). For the dithiocarhamate precursor, lithium bis(trimethylsilyl)amide can be used as the base and the polymerization proceeds at 35 The elimination temperature of these precursor polymers is typically lower than that of the sulfonium polymers with xanthate elimination at 160-250 °C and dithio-carbamate at 180 °C. It has been found that elimination of dithiocarbamate gave materials with reduced structural defects. Both xanthate and dithiocarbamate routes avoid the corrosive acid byproducts (HCl) present in the sulfonium elimination. This is particularly advantageous in device fabrication as adds have a negative impact on indium tin oxide electrodes and interfaces. ... 

Benzyl N-(p-chIorophenylthio)carbamate allowed to react 10 min. at -20 with K-tert-butoxide in dimethylformamide then 10 hrs. with p-nitrobenzyl bromide benzyl N-p-nitrobenzyl-N-(p-chlorophenylthio)carbamate (Y 87%) treated 15 min. with p-chlorobenzenethiol in dimethylformamide -> benzyl N-p-nitro-benzylcarbamate (Y ca. 100%). F. e., also N-carbobenzoxyamino acids, s. T. Ta-guchi and T. Mukaiyama, Chem. Lett. 1973, 1. 

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