Lithium amides reaction with carbon monoxide

In the carbonylation reactions, further reaction of the acyl lithium compounds with carbon monoxide can occur, but clean reaction can be achieved if the lithium amide is first converted to a copper derivative (Scheme 130) (79JOC3734). In the case of morpholine, reaction with allyl bromide gave a 93% overall yield of the amide product. 

V,7V-Diethylcarbamoyl trimethylsilane has been prepared by the reaction of bis(trimethylsilyl) sulphide with bis(A,A-diethylcarbamoyl) mercury (Scheme 30)16. Silylation of the carbamoyl cuprate reagent derived from a lithium amide, by addition of copper(I) cyanide and subsequent exposure to carbon monoxide (1 atm), is also effective75,110. Poor to moderate yields of carbamoyl silanes may be isolated by treatment of lithium silylamides with carbon monoxide and methyl iodide, in a reaction sequence involving a nitrogen to carbon silyl shift in an intramolecular silylation (Scheme 31)111. 

Formamides are usually not deprotonated a to nitrogen but at the formyl group [227-231], The resulting carbamoyl lithium derivatives (R2NCOLi), which can also be generated from deprotonated amines [351] or amides [352] and carbon monoxide, react with electrophiles E+ to yield the expected products (R2NCOE), despite the carbene character and consequent low stability of these intermediates [179, 351] (Scheme 5.39, see Section 5.4.7). Palladium-catalyzed versions of the reaction have been reported [353, 354],... 

The utility of carbonylation of lithium amides for the synthesis of complex molecules has been also demonstrated. V.V.V V -Tetrasubstituted ureas 5 were obtained in good yields by reaction of lithium alkyl amides in THF solution with carbon monoxide under mild conditions (0°C, 1013 mbar), followed by treatment with oxygen prior to work-up... 

N,N,N, N -Tetrasubstituted ureas 1049 have been obtained in variable yields (45-69%) by reaction of lithium aliphatic amides 1047 in THF solution with carbon monoxide under mild conditions (atmospheric pressure, 0 °C) followed by in situ oxidation with oxygen of the intermediate 1048 prior to work-up. The advantages of this method are the short reaction time and the use of molecular oxygen as oxidant [764]. 

A similar selenium insertion proceeds with lithium amides of secondary amines. In the presence of an isocyanide, lithium selenocarbamidates 2 are produced, which can be trapped with butyl iodide to give the corresponding iso-selenoureas 3 in good yields (Scheme 3) [5]. When the reaction is carried out under carbon monoxide atmosphere, the corresponding selenocarbamates are obtained [5]. 

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