Cyanation amide acetals

The reaction of anomeric sulfones with vinyl magnesium bromide in the presence of zinc bromide allows direct vinylation at the anomeric center. This reaction was the starting point of an approach for the synthesis of the C29 to C51 fragment of altohyrtin A [64]. The C29 to C44 (EF) portion of this compound has been prepared by a stepwise sequence involving anomeric cyanation, using the reaction of anomeric acetate in the presence of BF3-Et20. The anomeric cyanide was then elaborated to the Weinreb amide, which was condensed with an appropriate vinylic carbanion representing the C29 to C37 chain [298]. 

The principle of Wohler s method provides a method of very wide and varied applicability for the preparation of urea derivatives. Alkali cyanates and isocyanic and isothiocyanic esters on the one hand and ammonia, amines, amides, hydrazines, etc., on the other, undergo the reaction. When an alkali cyanate is used it is usually possible to work in aqueous solution and add the amine as a salt alternatively, the free amine can be used in dilute acetic acid room temperature or moderate temperatures usually suffice. A series of examples for the preparation of monoarylureas by this method is to be found in Organic Syntheses.64... 

A group of Russian workers [22 to 27] reported on the fluorination of mixtures of solid amines, amides, or cyano compounds with KF or CaF2. The reactions were carried out in a stream of F2 diluted with N2 at about -10 to +10°C. NF3 was one of the main products and was accompanied by fluorinated fragments of the compounds treated. The N-containing compounds studied include aliphatic amine hydrochlorides [22, 23], the amides of trifluoro- and difluoro acetic acid [24], potassium cyanate [25], silver and potassium thiocyanate [26], and a acetonitrile boron trifluoride complex [27]. 

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