Ethyl bromoacetate → (E)-6-[2-(2,6-Dichlorophenyl)ethenyl]-3,4,5,6-tetrahydro-4-hydroxy-4-methyl-2H-pyran-2-one

A solution of 6-(2,4-dichlorophenyl)-2-oxo-5-hexene-4-yl acetate (1.3 g, 4.3 mmole) and ethyl bromoacetate (0.47 ml, 4.2 mmole) in dry THF (10 ml) was added dropwise to a vigorously stirred slurry of activated zinc dust (490 mg, 7.5 mmole), cuprous bromide (29 mg, 0.2 mmole), diethylaluminum chloride (25% solution in toluene; 1.72 ml, 4.3 mmole) and dry THF (5 ml) under N2 at 20° C. Stirring was continued for 5 hours before quenching with pyridine (3.5 ml). After the addition of water (50 ml) the mixture was extracted with ether (3×80 ml). The combined ether extracts were washed with 1N HCl (2×25 ml), H2O (2×50 ml) and brine, then dried (MgSO4), filtered and evaporated leaving the crude title compound as a pale yellow oil (1.2 g); pmr (CDCl3) δ1.28 (3H, t), 1.33 (3H, t), 2.10 (3H, s).

1. custombefore quenching with pyridine (3.5 ml)
2. additionAfter the addition of water (50 ml) the mixture
3. extractionwas extracted with ether (3×80 ml)
4. washThe combined ether extracts were washed with 1N HCl (2×25 ml), H2O (2×50 ml) and brine
5. dry with materialdried (MgSO4)
6. filtrationfiltered
7. customevaporated

ORD record

ord-7ace549285bb4d8088ab480e966827be

Source dataset

uspto-grants-1984_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04459422