Crotyl 2,4-dichloro-5-methylphenyl ether (A) gave a mixture of the expected product, 2,4-dichloro-5-methyl-6-(α-methylallyl)phenol (B-2), and 2,4-dichloro-3-methyl-6-(α-methylallyl)phenol (C-2) when refluxed in dimethylaniline. Compound B-2 was converted to 2-methyl-6-oxo-l-cyclohexene(2-propionic acid) (H) by methylation, oxidation with permanganate-periodate, reduction with lithium-liquid ammonia, and acid hydrolysis. The phenol B-2 and its methyl ether were cyclized by concentrated sulfuric acid to cis- and trans-2,3-dihydro-2,3,4-trimethyl-5,7-dichlorobenzofurans (J and I); these were separated, configurations were assigned, and the equilibration of the cis and trans forms studied. Treatment of B-2 and its methyl ether with ICl gave the cis- and trans-iodomethyl compounds, M and L, whose configurations have been related to those of the dimethyl compounds J and I. J2H-3H for the cis- and trans-2,3-dihydrobenzofurans have been measured and compared with calculated values.
ASJC Scopus subject areas
- Organic Chemistry