Furan, reaction with bromine and methanol to yield 2,5-dimethoxy-2,5-dihydrofuran

Furan, reaction with bromine and methanol to yield 2,5-dimethoxy-2,5-dihydrofuran, 40, 29 Fuean, 2,5-DmYDRO-2,5-dim-ethoxy-, 40, 29... 

An alternative route starts from furan (19). Reaction with bromine in methanol leads to 2,5-dimethoxy-2,5-dihydrofuran (20) which is transformed to but-2-ene-1,4-dial bisdimethyl-acetal (21). Double enol ether condensation with 1-propenyl methyl ether (22), followed by acetal hydrolysis and elimination, provides crystalline (all- -Cio-dialdehyde 8 in an overall yield >50% [13]. 

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