Herein, the first Lewis acid-catalyzed ring-opening reaction of bicyclobutanes (BCBs) with acyclic thioamides for the concise, modular synthesis of 1,1,3-trisubstituted cyclobutanes is described. These products feature valuable iminothioether-substituted cyclopropane moieties and single-configuration tetrasubstituted carbon stereocenters. The reaction proceeds under mild conditions and accommodates diverse acyclic thioamides and substituted acyl-BCBs, exhibiting excellent nucleophilic selectivity (S-H/N-H > 99/1) and chemoselectivity (trans/cis > 98/2). Derivatization experiments and single-crystal X-ray structural analysis further confirmed the synthetic utility of this reaction.
Zhang et al. (Tue,) studied this question.