Allyl bromide → tert-butyl ((5RS,6SR)-6-allyl-5-(2-fluoro-5-nitrophenyl)-2,2,5-trimethyl-1,1-dioxido-5,6-dihydro-2H-1,4-thiazin-3-yl)carbamate

Participants

Reaction Conditions

Reaction Steps

To a solution of tert-butyl (5-(2-fluoro-5-nitrophenyl)-2,2,5-trimethyl-1,1-dioxido-5,6-dihydro-2H-1,4-thiazin-3-yl)carbamate (230 mg, 0.536 mmol) in THF (5 ml) was added lithium diisopropylamide, (2.0 M solution in tetrahydrofuran/heptane/ethylbenzene) (0.803 ml, 1.607 mmol) dropwise at −78° C. and the mixture was stirred for 20 min at the −78° C. To a resulting dark solution, allyl bromide (0.139 ml, 1.607 mmol) was added dropwise and the mixture was stirred for another 20 min. The reaction was quenched with NH4Cl solution at −78° C., the flask was removed from the bath and allowed to reach RT. The mixture was extracted with ethyl acetate, organic layer was washed with brine, concentrated and the concentrated crude residue was separated on 12 g RediSep Gold column using 5-50% EtOAc in heptane solvent gradient to afford tert-butyl ((5RS,6RS)-6-allyl-5-(2-fluoro-5-nitrophenyl)-2,2,5-trimethyl-1,1-dioxido-5,6-dihydro-2H-1,4-thiazin-3-yl)carbamate (120 mg, 0.256 mmol, 47.7% yield) as major diastereomer and tert-butyl ((5RS,6SR)-6-allyl-5-(2-fluoro-5-nitrophenyl)-2,2,5-trimethyl-1,1-dioxido-5,6-dihydro-2H-1,4-thiazin-3-yl)carbamate (20 mg, 0.043 mmol, 7.9% yield) as minor diastereomer.

Provenance & Evidence