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

Participants

Reaction Steps

A vial was charged with K2CO3 (0.22 g, 1.56 mmol, 2 eq.), CuI (0.01 g, 0.08 mmol, 0.1 eq.) and trans-1,2-cyclohexane diamine (0.01 g, 0.08 mmol, 0.1 eq.), rac-(4aR*,8aR*)-tert-butyl 2-oxohexahydro-2H-pyrido[4,3-e][1,3]oxazine-7(3H)-carboxylate (Preparation A, 0.2 g, 0.78 mmol) and flushed with nitrogen for 5 min. A solution of 6-iodo-2,3-dihydrobenzo[b][1,4]dioxine (0.21 g, 0.78 mmol, 1.01 eq.) in dry dioxane (0.78 mL) was added and the resulting suspension was at 110° C. for 40 h. The reaction mixture was cooled to rt and filtered over Celite. The solid was washed by EA (2×10 mL). The filtrate was concentrated to dryness and the residue was purified by CC (DCM/MeOH 49:1 to 19:1) to give the title compound as a beige foam (0.19 g).

Provenance & Evidence