This reaction has been carried out numerous times within the lab on both large and small scales. We have found that the largest scale possible due to work up considerations is the scale reported above. The addition of the sodium cyanide can sometimes cause problems due to the low solubility in DMSO. This problem is easily overcome by simply adding the NaCN portionwise to a more dilute solution of the bromide. A further practical consideration is the aqueous extraction, which sometimes causes problems due to the DMSO preventing separation of the two layers. This can be overcome by the addition of a small amount of salt to the aqueous layer. NB All glasswear must be cleaned by submersion in bleach for 24 h after the reaction. Local safety rules should be consulted before working with cyanides (eg breathing apparatus, antidote etc).