Regiospezifische Reduktionen von 1,3,3‐trisubstituierten Succinimiden mit Diboran

Abstract

Regiospecific reduction of 1,3,3‐trisubstituted succinimides by diboraneIt is possible to reduce 1,3,3‐trisubstituted succinimides regiospecifically by diborane at the less substituted carbonyl group to yield the corresponding lactams. This method was used specially for the reduction of 2,8‐diazaspiro[4,5]decane‐1,3‐diones to 2,8‐diazaspiro[4,5]decan‐1‐ones. These results are in contrast to those of Speckamp et al. [4a‐h] in which sodiumborohydride/HCl was the reducing agent. Possible explanations for the selective reductions are discussed, using the principles of steric approach control of Dunitz & Bürgi [6] and of Baldwin [8].