Isothiourea-catalyzed annulations of 2-acyl benzazoles and α,β-unsaturated acyl ammoniums are tuned to form lactams or lactones (up to 99% ee). Computations highlight the governing roles of S⋯O and CH⋯O interactions.
异硫脲催化的2-酰基苯并唑与α,β-不饱和酰基铵的环合反应可以被调节形成内酰胺或内酯(对映体过量高达99%)。计算表明S⋯O和CH⋯O相互作用在调控反应中起主导作用。