The cycloaddition of substituted furans to the diterpenoid aryne (39),
generated by in situ diazotization of the anthranilic acid (1) follow
ed by cleavage of the annulated 1,4-epoxydecahydrochrysenes, provides
a convenient method for the preparation in high yield of the previousl
y unknown 1-substituted octahydrochrysen-4-ols. Use of 1,3-dipoles und
er the same procedure, or under a modified procedure involving pre-iso
lation of the diazonium tetrafluoroborate salt (9), gave novel annulat
ed heterocyclic products directly. Attempted [2+2] cycloadditions of e
lectron-rich alkenes to the diterpenoid aryne (39) were largely unsucc
essful but reaction with 1,1-dimethoxyethene by using in situ diazotiz
ation gave a product derived from an initial [2+2] cycloaddition.