Bicyclo[1.1.1]pentyl Sulfoximines: Synthesis and Functionalizations

Herein we present the first synthesis of bicyclo[1.1.1]pentyl (BCP) sulfoximines from the corresponding sulfides. Both BCPs and sulfoximines are bioisosteres used in medicinal chemistry and therefore desirable motifs. The access to BCP sulfides was enabled by the thiol addition to [1.1.1]propellane as published before. A broad scope with specific limitations was discovered for the sulfoximination. To diversify the sulfoximines, N-acylations and N-arylations were performed. As the N-arylation was low yielding we optimized the copper(I) catalyzed reaction. A wide range of aryl iodides could be deployed and competitive reactions showed that aryl bromides react equally fast. In a scale-up we prepared a suitable precursor for a BCP drug analogue.
In this work several molecular structures could be determined by single-crystal X-ray diffraction.