Au(I)-Catalyzed Cyclization of Methyl 2-(2-Alkynylphenylethynyl) Benzoates to 6H-Dibenzo[c,h]chromen-6-ones and Synthesis of Arnottin I

• Main Authors: Chia-Ling Hsu, 許嘉玲
• Other Authors: Ming-Jung Wu
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/92891328567668102702

碩士 === 國立中山大學 === 化學系研究所 === 100 === Gold catalysts have the characteristic of promoting nucleophilic reaction. The cyclization reaction of enediynes catalyzed by gold activated by silver in toluene at 100oC to give 6H-dibenzo[c,h]chromen-6-ones (63), 6H-benzo[c]chromen-6-one (66) and Arnottin I (10) is described. Treatment of enediynes (61、65) with 5 mol% of Ph3PAuCl and 10 mol% of AgSbF6 in toluene at 100oC gave 6H-dibenzo[c,h]chromen-6-ones (63) and 6H-benzo[c]chromen-6-one (66) in good yield. In addition to using gold catalyst, electrophilic reagents employed in the reaction caused one cyclization instead of two cyclization. Furthemore, a mechanistic study and GC-MS data showed that the toluene could participate in the reaction. Enediynes (73) can be synthesized by a series of organic synthesis with few steps. Treatment of enediynes (73) with 5 mol% of Ph3PAuCl and 10 mol% of AgSbF6 in toluene at 100oC gave natural product-Arnottin I (10).