One Pot Synthesis of Polycyclic Oxygen Aromatics. Part IV. Reaction of THP Ether of 2-Bromomethyl Phenols

Article abstract of DOI:10.1016/S0040-4020(01)86351-1

Reaction of 2-bromomethyl-1-(2'-tetrahydropyranyloxy)benzene 3a with tetrachlorocatechol (TCC) in acetone in presence of anhydrous K2CO3 resulted in the formation of diastereomeric products to which cis- and trans- 6-chloro-8-hydroxy-8-(2-oxopropyl)spiro<9H-benzoxanthen-9,2'(1'H)benzofuran>-7(8H)-one (7a and 8a) structures were assigned, along with tetrachlorocatechol ethers (5a and 6a).Similar reaction of 3a with tetrabromocatechol (TBC) gave the expected monobromo compounds 7d and 8d along with the ethers 5d and 6d.When the reaction was repeated with substrates 3b-c with TCC/TBC in ketonic solvents (acetone/methyl ethyl ketone), the corresponding compounds 5b-c to 8b-c, 5e-f to 6e-f, 7e-g and 8e-h were obtained.A suitable explanation has been given for the formation of acetonyl compound 6 in this reaction.