“…In most case, the product is a mixture (more than one structural isomer) [43]. Recently, Shan and coworkers reported that condensations of (1S,2S)-ANP with cyclohexanone, acetone, butanone, and pentan-3-one in toluene or xylene by azeotropic distillation in the absence of catalyst afforded almost quantitatively 1,2-cyclocondensation derivatives via a highly efficient chemoselectivity [44].…”