Radical Reactions of Carbohydrates

Volume II: Radical Reactions in Carbohydrate Synthesis

Chapter 16: Nitriles and Isonitriles

Chapter 16 is in a portable document file (pdf) and can be viewed by clicking the blue, Chapter 16 button below. The drawing underneath the button pictures the addition of a carbon-centered, carbohydrate radical to a cyano group. Beside the drawing is a description of the reaction. Below the drawing and its description is a summary of Chapter 16.

Chapter 16: Nitriles and Isonitriles

This drawing shows a radical addition to a cyano group.

Drawing Description

Radical reactions of carbohydrate nitriles usually involve internal addition in which a carbon-centered radical generated in close proximity to a cyano group forms a new ring system. An example is shown in the drawing on the left (Scheme 9 in Chapter 16), where the radical centered on C-6 in 11 adds to the cyano group as a part of a sequential process

Summary of Chapter 16

When compared to reactions of halogenated carbohydrates or O-thiocarbonyl compounds, radical reactions of nitriles and isonitriles are few in number. The primary reaction for isonitriles is isocyano group replacement by a hydrogen atom. For nitriles the only reaction of significance is internal addition of a carbon-centered radical to a cyano group to form a cyclic imino radical.

Radical reactions can be involved in nitrile and isonitrile synthesis. Isonitriles are formed from reaction of isothiocyanates with tri-n-butyltin hydride. Nitriles are produced by addition of a carbon-centered radical to t‑butyl isonitrile and subsequent elimination of the t-butyl radical.