Studies toward Lewis basic thiocarbamate and thiourea mediated bromolactonization: the effect of a trace amount of water on the reactivity and enantioselectivity

The effects of trace amounts of water on thiocarbamate- and thiourea-catalyzed bromolactonization reactions are studied. It was found that the thiourea- and the N–Me thiocarbamate-catalyzed bromolactonization reactions were sensitive to trace amounts of moisture. In contrast, the N–H thiocarbamate-catalyzed bromolactonization proceeded equally smoothly in both anhydrous and non-anhydrous solvents.