Di-tert-butyl dicarbonate → HCID 11974441, compound

Participants

Reaction Steps

Alternative resolution procedure: A solution of Example 39A (510 mg) was dissolved in methanol (1 mL) and CH2Cl2 (1 mL), and then (trimethylsilyl)diazomethane solution (0.4 mL, 2M in ether) was added. After ten minutes, acetic acid (0.2 mL) was added. The resultant solution was concentrated in vacuo and partitioned between ethyl acetate and bicarb. The organic extract was washed with brine and dried over sodium sulfate. The crude material was deprotected using the procedure of Step B in Example 20D; and the product was partitioned between sodium bicarbonate and ethyl acetate. The organic phase was washed with brine and dried over sodium sulfate. The crude product (410 mg) was dissolved in 30 ml of ethanol. 420 mg (0.8 eq) of dibenzoyl (D)-tartaric acid was added, and the mixture was stirred until homogeneous. The resultant solution was allowed to stand overnight and the crystalline product was collected by filtration (yield 39%, ee>98%). The crystalline solid was dissolved in tetrahydrofuran (10 mL). Then, di-tert-butyl dicarbonate (1.1 eq.) and saturated sodium bicarbonate solution (5 mL) were added. After thirty minutes, the reaction mixture was concentrated and subjected to column chromatography (eluting with 20% ethyl acetate/hexane) to give the title compound.

Provenance & Evidence