Me3SiI-promoted reaction of salicylic aldehydes with ketones: a facile way to construct benzopyranic [2,3-b]ketals and spiroketals
作者:Feijun Wang、Mingliang Qu、Xi Lu、Feng Chen、Feng Chen、Min Shi
DOI:10.1039/c2cc32545d
日期:——
Me3SiI-promoted reaction of salicylic aldehydes with ketones via arylmethylation at the α-site of the carbonyl group and cyclodehydration of keto-diol provided a facile way to construct heteroannular ketals, furnishing benzopyranic [2,3-b]ketals and spiroketals in moderate to good yields.
An aromatic diol, e.g. hydroquinone, or a monoalkyl ether of an aromatic diol, e.g. the monomethyl ether of hydroquinone, is produced by transesterifiying a carboxylate ester of said aromatic diol or monoalkyl ether with an alcohol or phenol such as ethanol. A newly-formed ester such as ethyl acetate is co-produced by the reaction. The carboxylate ester is preferably produced by subjecting an aromatic ketone containing a hydroxy or alkoxy radical on the aromatic ring, e.g. 4-hydroxyacetophenone, to a Baeyer-Villiger oxidation.