“…Substrates 1a – 1d , 1f – 1k , 1m – 1q , 4a , 4b , 4d , 4e , 4m , 4s , 4u , and 7 were purchased from commercial suppliers without further purification. Substrates 1e , 1l , 2 , 4c , 4f , 4g , 4h , 4i – 4r , ,− and 4t were synthesized according to the reported procedures. Their NMR data and melting points were identical to those reported in the literature.…”