“…Vieregge and co-workers were the first group to report catalytic CAM reactions in 1959, employing BF 3 as reaction promoter . From developments in the field in the past few decades, it has been established that the CAM reaction can be promoted through either the activation of the carbonyl moiety, which can be achieved by oxophilic Lewis acid (such as FeCl 3 , GaCl 3 , SbF 5 and triflate salts of Zn, Yb, In, and Sc) or Brønsted acid (pTSA, TfOH, TFA, and HBF 4 ) catalysis, or the activation of the alkyne moiety by employing π-electrophilic Lewis acid (such as AgSbF 6 , , AuCl 3 , or Pd-complexes) catalysis. , However, many of these reactions required harsh conditions or used high loadings of transition metal catalysts. Several catalytic systems are applicable to only one type of either intermolecular or intramolecular CAM reactions.…”