The cyclisation of benzonitrile 3,3-diarylallyl ylides to give 3H-2-benzazepines: Substituent directive effects and mechanism
作者:Paul W. Groundwater、John T. Sharp
DOI:10.1016/s0040-4039(00)96047-7
日期:1987.1
reaction of imidoyl chlorides with base, cyclised by 1,7-ring closure to give 3H-2-benzazepines (9), in contrast to analogous diazo-compounds (1) which prefer 1,5-electrocyclisation. Asymmetrically placed substituents (R in 14b) favour substitution at the (2′) position irrespective of their polar electronic effects. Deuterium labelling studies have shown that the cyclisation step is irreversible for nitrile
Substituent directive effects in 1,2-benzodiazepine synthesis via electrocyclic aromatic substitution by the diazo-group: a rearrangement of 9- to 7-substituted 3H-1,2-benzodiazepines
作者:Thomas K. Miller、John T. Sharp、H. Raj Sood、Edward Stefaniuk
DOI:10.1016/s0040-4039(00)74582-5
日期:1980.1
The directive effect of aryl-substituents on the site of ring closure in the electrocyclisation of 1-aryl-3-diazoalkenes has been investigated. At 80°C the product ratio is determined by kinetic control but for some substituents the kinetically favoured 9-substituted 3-1,2-benzodiazepines undergo a new rearrangement to their more stable 7-substituted isomers.