TY - ECHAP DO - 10.1055/sos-SD-213-00137 SN - 9783131751218 SN - 9783132064515 LA - EN AU - te Grotenhuis,C.; Schoonen,L.; Rutjes,F. P. J. T. TI - 2.5.2 Cyanation of Epoxides PB - Georg Thieme Verlag KG CY - Stuttgart PY - 2014 UR - http://www.thieme-connect.com/products/ebooks/lookinside/10.1055/sos-SD-213-00137 T3 - Science of Synthesis VL - 2013/8 DA - 2015/10/26 KW - epoxide KW - cyanide KW - cyanation KW - nucleophilic ring opening KW - Lewis acid activation KW - β-hydroxy nitrile KW - β-cyanohydrin AB - Opening of epoxides with cyanide yields β-cyanohydrins (β-hydroxy nitriles), which are synthetically versatile intermediates that can be readily converted into a wide array of new functional groups. During the ring-opening reaction two contiguous stereocenters are generated, which can be controlled in several ways. When the reaction is performed without activation, terminal epoxides can be opened such that attack will take place at the least hindered carbon atom. Addition of a hard Lewis acidic catalyst will lead to activation of the epoxide, due to coordination to the epoxide oxygen atom, allowing the use of electronically and sterically more demanding substrates. Furthermore, ligands surrounding the metal of the catalyst can direct to which position of the epoxide attack will take place. If enantiopure ligands are used, meso-epoxides can be desymmetrized, resulting in the formation of a single enantiomer of the β-hydroxy nitrile product. T2 - C-1 Building Blocks in Organic Synthesis 2 ER -