The isomeric products could be formed due to fragmentation of intermediate carbonium ion followed by ring closure and dehydrogenation.

1.9.5.5 Deprotection of p-Methoxybenzyl Ethers

p-Methoxybenzyl ether could be deprotected selectively using DDQ in the presence of other protecting groups such as acetals, RO-Bn, RO-MOM, RO-MEM, RO-THP, RO-TBS, benzoyl, tosyl, acetate groups or epoxides (Scheme 14).

Scheme 14

Examples:

What products would you expect in the following reactions ?

Text Books:

V. K. Ahluwalia, R. K. Parashar, Organic Reaction Mechanisms , Narosa, New Delhi, 2002.

M. B. Smith, Orgnic Synthesis , 2 nd Ed., McGraw Hill, New York, 2004.