Selenocyanation of alkyl mesylates: To the mesylate, dissolved in THF (0.1 M), were added NaI (3.0 equiv.), 18-crown-6 (1.1 equiv.) and KSeCN (2.2 equiv.). The suspension was heated to 50 °C for 16 h, then diluted with brine and DCM. The aqueous layer was extracted with DCM, and the combined organic phases were dried over MgSO4, filtered and concentrated in vacuo. Flash column purification of the oily orange crude afforded alkyl selenocyanates as colourless or pale yellow solids.