1,8-Diazabicyclo(5.4.0)undec-7-ene → (+/-)-(3aR*,8aS*)-1,2,3,3a,8,8a-Hexahydro-1,3a,8-trimethylpyrrolo-[2,3-b]indol-4-yl (R)-(alpha-methylbenzyl)carbamate

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Reaction Steps

cis-(±)-1,2,3,3a,8,8a-Hexahydro-1,3a,8-trimethylpyrrolo [2,3-b]indol-4-ol (2g) was dissolved in degassed THF (200 ml). DBU (0.8 ml) was added to the mixture followed by R-(+)-α-methylbenzyl isocyanate (2 g). The reaction was stirred at room temperature overnight under nitrogen. The solvent was evaporated under reduced pressure and the residue was purified using Prep 500 chromatography (4% MeOH/DCM) to yield 1.2 g of a solid. This material was combined with 600 mg of identically prepared material, which was found to be pure by thin layer analysis. The combined product was triturated with isopropyl ether and filtered to yield 1.8 g of (±)-(3aR*, 8aS*)-1,2,3,3a,8,8a-hexahydro-1,3a,8-trimethylpyrrolo [2,3-b]indol-4-yl (R)-(α-methylbenzyl)carbamate, m.p. 151°-155° C.

Provenance & Evidence