An unusual reaction of chalcone epoxides is observed where chalcone epoxides on heating
with iodine in methanol leads to α,α-dimethoxyacetophenones, through C–C bond cleavage
followed by acetalization of the formyl group. The process occurs through ring opening
of the chalcone epoxide by methanol to form β-methoxy alcohol, cleavage of the C–C
bond in the latter to form α-ketoaldehyde, and acetalization of the formyl group to
give the product. The protocol provides direct access to α,α-dimethoxyacetophenones
from chalcone epoxides.
Key words
oxidative cleavage - chalcone epoxides - iodine - α,α-dimethoxyacetophenones - acetals
- α-ketoaldehydes