Cyanotrimethylsilane cyclic

Cleavage of epoxides andoxetanes.5 In the presence of diethylaluminum chloride as catalyst, cyanotrimethylsilane reacts with epoxides and oxetanes regioselectively to give open-chain products in which the CN group is attached to the less substituted a-carbon of the cyclic ether. 

The five-membered hypervalent iodine heterocycles, benziodoxoles, are commonly used as convenient radical precursors [3,33]. The main advantage of benziodoxoles over the non-cyclic hypervalent iodine reagents is the higher thermal stability allowing the preparation of otherwise unstable derivatives with I-Br, I-OOR, I-N3, and I-CN bonds. The stable cyanobenziodoxoles 36-38 are prepared in one step by the reaction of cyanotrimethylsilane with the respective hydroxybenziodoxoles 35 (Scheme 16) [34, 35], or from acetoxybenziodoxole... 

A-chlorosuccinimide provides (3 S, 4 S)-3,4-bis(TBSO)-l-chloropyrrolidine (771). Dehydrochlorination with DBU in benzene affords a cyclic imine that reacts with cyanotrimethylsilane in the presence of catalytic zinc iodide to afford an epimeric mixture of aminonitriles. Acidic hydrolysis of the nitrile, esterification of the resulting acid, Cbz-protection of the basic amine, and chromatographic separation affords 772 in 28% yield and 774 in 42% yield. These are converted respectively to either (25, 35,45)-3,4-dihydroxyproline (773) or (2R,3>S,4S)-3,4-dihydroxyproline (775) [230] (Scheme 169). 

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