Triphosgene → 3-[(S)-1-(4-Bromo-phenyl)-ethyl]-1-oxa-3-aza-spiro[5.5]undecane-2,9-dione

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Reaction Steps

The title compounds are prepared from 8-{2-[(S)-1-(4-bromo-phenyl)-ethylamino]-ethyl}-1,4-dioxa-spiro[4.5]decan-8-ol and triphosgene following a procedure analogous to that described in step 3 of Intermediate 1. The ketal group is partially cleaved under these conditions to give a mixture of the title compounds that is separated by chromatography on silica gel (cyclohexane/ethyl acetate 9:1→1:1). 11-[(S)-1-(4-bromo-phenyl)-ethyl]-1,4,9-trioxa-11-aza-dispiro[4.2.5.2]pentadecan-10-one: Yield: 6% of theory; LC (method 1): tR=3.65 min; Mass spectrum (ESI+): m/z=410/412 (Br) [M+H]+.

Provenance & Evidence