Isonitriles from epoxides

Conjugated isonitriles. Isocyanoalkyl epoxides undergo ring opening by reaction with LHMDS. The ( /Z)-isomer ratios are different from (usually higher than) those arising from using LDA. 

Unusual triethylamine-catalysed rearrangements of bicyclic endoperoxides derived from substituted cycloheptatrienes have produced383 a variety of products (see, e.g., Scheme 80). Ab initio calculations have shown that energised 2,3-epoxypropoxide anions undergo a degenerate Payne rearrangement in the gas phase via a three-centre mechanism.384 It has been reported385 that treatment of isonitrile epoxides (330) with... 

Silyl cyanides react enantioselectively with such electrophiles as aldehydes, ketones, imines, activated azines, or,/ unsaturated carbonyl compounds, epoxides, and aziridines in the presence of chiral Lewis acid catalysts to give functionalized nitriles, versatile synthetic intermediates for hydroxy carboxylic acids, amino acids, and amino alcohols (Tables 3-6, 3-7, 3-8, and 3-9, Figures 3-6, 3-7, and 3-8, and Scheme 3-154). ° Soft Lewis acid catalytst, the reaction of epoxides with trimethylsilyl cyanide often leads to isonitriles, which are derived from silylisonitrile spiecies (Schemes 3-155 and 3-156). Soft Lewis base such as phosphine oxide also catalyzes the reaction and cyanohydrin silyl ethers of high ee s are isolated. 

Me SiCl in ether to give chlorohydrms in quantitative yield. A rather interesting change in the products obtained from the reaction of rfe SiCN with epoxides is brought about by the type of catalyst used. When propene oxide is treated with Me SiCN in the presence of Et AlCl the product is the nitrile (114) (83%) An entirely different product, the isonitrile is obtained however using Znl2 catalyst thus cyclopentene oxide affords (115) (77%). ... 

---