11-undecenethiol was prepared from 11-undecenyl bromide via the well-known thiourea method. 11-bromoundecene (5.4 g, 5 mL, 23 mmol) was dissolved in 80 mL Ar-sparged ethanol with 1.90 g (25 mmol) thiourea and refluxed overnight. 50 mL aqueous 10% w/vKOH was added and reflux continued 5 hrs. The pH was reduced to 2 by addition of 5% HCl solution and extracted with diethyl ether, washing 1x with water and 1x with brine. Removal of solvent in vacuo gave a white solid, which after dissolving in DCM and passing over a plug of silica gel gave the product as a white, slightly waxy solid after rotary evaporation.