Potassium Carbonate → Rac-(4aR*,8aR*)-tert-butyl 3-(4-(4-methoxybenzyl)-3-oxo-3,4-dihydro-2H-benzo[b][1,4]oxazin-6-yl)-2-oxohexahydro-2H-pyrido[4,3-e][1,3]oxazine-7(3H)-carboxylate

Participants

Reaction Conditions

Reaction Steps

In a 7 mL sealed vial were introduced 6-iodo-4-(4-methoxybenzyl)-2H-benzo[b][1,4]thiazin-3(4H)-one (0.2 g, 0.486 mmol), rac-(4aR*,8aR*)-tert-butyl 2-oxohexahydro-2H-pyrido[4,3-e][1,3]oxazine-7(3H)-carboxylate (Preparation A, 0.15 g, 0.584 mmol, 1.2 eq.), potassium carbonate (0.134 g, 2 eq.), (R,R)-(−)-N,N′-dimethyl-1,2-cyclohexanediamine (0.01 g, 0.06 mmol, 0.1 eq.), CuI (0.11 g, 0.57 mmol, 1 eq.) and dioxane (2.3 mL). The suspension was stirred at 100° C. for 2 days. The mixture was cooled to rt, diluted with DCM/MeOH (9:1, 2 mL) and filtered. The yellow salt obtained was washed with DCM/MeOH (9:1, 2×10 mL). The combined filtrates were concentrated under reduced pressure. The residue was purified (DCM/MeOH 9:1) to afford the title compound as a greenish foam (0.15 g).

Provenance & Evidence