zopyran‐1‐ones), 4‐substituted 3,4‐dihydro‐3‐methoxyisocoumarins 2, can be obtained by a one‐pot process from α‐substituted 2‐bromo‐β‐methoxystyrenes 1. Thus, lithium 2‐(1‐aryl(or methyl)‐2‐methoxyethenyl)benzoates are conveniently generated via the Br/Li exchange between 1 and BuLi, followed by the action of CO2 on the resulting α‐substituted 2‐lithio‐β‐methoxystyrenes. Upon treating with concentrated
可以通过一锅获得一种新型的异香豆素(= 1 H-异色n-1-酮= 1 H -2-苯并吡喃-1-酮),4-取代的3,4-二氢-3-甲氧基异香豆素2。由α-取代的2-溴-β-甲氧基苯乙烯制备1。因此,通过1和BuLi之间的Br / Li交换可方便地生成2-(1-芳基(或甲基)-2-甲氧基乙烯基)苯甲酸锂,然后通过CO 2对生成的α-取代的2-lithio-苯甲酸作用β-甲氧基苯乙烯。在室温下用浓盐酸处理后,这些苯甲酸锂会发生内酯化反应,从而以相对较高的收率提供所需的3,4-二氢异香豆素2。
Synthesis of 1,3-Diaryl-2-methoxyindenes by Hydriodic Acid–Catalyzed Cyclization of Aryl[2-(1-aryl-2-methoxyvinyl)phenyl]methanols
two-step method for the synthesis of 1,3-diaryl-2-methoxyindenes from1-(1-aryl-2-methoxyvinyl)-2-bromobenzenes has been developed. Thus, the reaction of 2-(1-aryl-2-methoxyvinyl)phenyllithiums, generated in situ by halogen–lithium exchange between 1-(1-aryl-2-methoxyvinyl)-2-bromobenzenes and butyllithium, with aromatic aldehydes gives aryl[2-(1-aryl-2-methoxyvinyl)phenyl]methanols, which in turn are treated
3-Substitued benzo[b]thiophenes were synthesized in reasonable overall yields from alpha-substituted 2-bromo-beta-methoxystyrenes. Thus, the bromine-lithium exchange between these bromostyrenes with butyllithium in diethyl ether at 0 degrees C followed by reaction with sulfur afforded the corresponding a-substituted beta-methoxy-2-sulfanylstyrenes. These were then treated with an equimolar amount of concentrated hydriodic acid in acetonitrile at room temperature to give the desired products.