Isocyanates from isonitriles

Phenyl-3-methyl-l,3,2-oxazaphospholidine Isonitriles from isocyanates... 

More recently, Belzner et al. reported a new type of oxygen transfer reaction from isocyanates to bis[2-(dimethylaminomethyl)phenyl]silylene (8)18 which was thermally generated from the corresponding cyclotrisilane 7, and they obtained some convincing results of the involvement of silanone 9 (Scheme 3). However, they found that silanone 9 is not stable enough to be isolated. Only cyclic di- and trisiloxanes 10 and 11 (i.e., the cyclic dimer and trimer of the silanone 9) were obtained together with the corresponding isonitrile as other main products when... 

Koenig GM, Wright AD, Angerhofer CK. (1996) Novel potent antimalarial diterpene isocyanates, isothiocyanates, and isonitrile from tropical marine sponge Cymbastela hooperi. J Org Chem 61 3259-3267. 

Isonitriles also undergo carbene-like reactions with isocyanates and coreagents. For example, two isomeric [1+2+2] cycloadducts 50 and 51 are obtained from nitroso compounds, isonitriles and isocyanates. The reaction proceeds via addition across both the C=N and the C=0 bonds of the isocyanate . 

According to Scheme 4 elimination of a proton from the iminodiazonium ion (I) forms the nitrile. Rearrangement of the ion (I) leads to formanilide. But there are no data available supporting these ideas. Another possible way for the formation of nitrile is a rearrangement of the iminocarbonium ion (II) of the type which occurs in the isomerization of isonitriles to nitriles". It was found that in 71.2-90.4% sulphuric acid, phenyl isocyanate is converted quantitatively into formanilide. For a better understanding of the... 

The retrosynthetic approach to welwitindolinone A isonitrile (6) used by the Wood group is shown in Scheme 33. After recognition of the possibility of deriving the vinyl isonitrile fragment from a ketone, the disconnection of 6 to 140 was proposed. A literature report of a samarium (II) iodide-mediated reductive coupling of acrylates with isocyanates to give amides, which could be expected to lead to a new spirooxindole synthesis, prompted the disconnection of 140 to 141. This compound was to be obtained from the readily available cyclohexadiene derivative 143, by way of bicyclic ketone 142. 

The compound reacts with alcohols, phenols and amines to form products similar to those obtained from the corresponding reaction with COCI [1358]. Depending upon the conditions and stoicheiometry, carbonates and chloroformates [612,1380], carbamates [1380], isocyanates [1184] and ureas [938] can be obtained with diphosgene, in addition to more complicated products such as carbamoyl chlorides, imidic chlorides, carboxylic acid chlorides, isonitriles and IV-carboxy-Q-amino acid anhydrides [1358]. 

As the third component in the reaction of isocyanates with isonitriles enamines can also be used In this three-component reaction the isonitrile can be replaced by sulfur. Five-membered ring heterocycles are also formed from two equivalents of isocyanates and 2,2-bis(dialkylamino)-acetonitrile. This reaction proceeds via initial dissociation of the nitrile with formation of an isonitrile . 

Bromine dimethyl sulfoxide Isocyanates from isonitriles... 

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