Dorokhov VS, Nelyubina YV, Ioffe SL, Sukhorukov AY. Asymmetric Synthesis of Merck's Potent hNK
1 Antagonist and Its Stereoisomers via Tandem Acylation/[3,3]-Rearrangement of 1,2-Oxazine
N-Oxides.
J Org Chem 2020;
85:11060-11071. [PMID:
32786617 DOI:
10.1021/acs.joc.0c01322]
[Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An asymmetric total synthesis of Merck's hNK1 antagonist and three of its stereoisomers was accomplished in 10 steps. The synthesis involves a stereoselective assembly of 1,2-oxazine N-oxide by the [4 + 2]-cycloaddition, site-selective C-H oxygenation using a novel tandem acylation/[3,3]-rearrangement process and the reductive 1,2-oxazine ring contraction into a pyrrolidine ring as key stages. Using this strategy, the fused pyrrolidine subunit was constructed with exceptionally high regio- and stereoselectivities. The approach described here can be used to access enantiopure 3,4-disubstituted prolinols, which are frequently found in pharmaceutically relevant molecules and organocatalysts.
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