1460-1466The O-alkylation (allylation/propargylation)
of 3,5-dibromo-4-hydroxybenzaldehyde 1 and the corresponding acetophenone
2 results in the formation of aryl-aryl coupled product by loss of
formyl groups, aryl-aryl ether and aryloxy acetone in addition to the expected O-
allyl/ propargyl ethers. While the
thermal Claisen rearrangement of allyl ethers 1 and 2 furnishes the
C-allyl products by loss of bromine, the propargyl ether 7 surprisingly
resisted rearrangement and underwent oxidation to yield the corresponding carboxylic
acid