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Enantioselective direct Mannich-type reactions of 2-benzylpyridine N-oxides catalyzed by chiral bis(guanidino)iminophosphorane organosuperbase.

ABSTRACT: 2-Benzylpyridine N-oxides possessing less acidic ?-protons were utilized as pronucleophiles for the first time in enantioselective addition reactions under Brønsted base catalysis. A chiral bis(guanidino)iminophosphorane was able to overcome the inherent issue of low acidity of the pronucleophiles, establishing the diastereo- and enantioselective direct Mannich-type reaction with N-Boc imines. The control experiments indicated that the N-oxide moiety of the substrates played a critical role in achieving the high stereoselectivity.

SUBMITTER: Hu Q

PROVIDER: S-EPMC5944382 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature

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Enantioselective direct Mannich-type reactions of 2-benzylpyridine N-oxides catalyzed by chiral bis(guanidino)iminophosphorane organosuperbase.

Hu Qiupeng Q Kondoh Azusa A Terada Masahiro M

Chemical science 20180420 18

2-Benzylpyridine N-oxides possessing less acidic α-protons were utilized as pronucleophiles for the first time in enantioselective addition reactions under Brønsted base catalysis. A chiral bis(guanidino)iminophosphorane was able to overcome the inherent issue of low acidity of the pronucleophiles, establishing the diastereo- and enantioselective direct Mannich-type reaction with <i>N</i>-Boc imines. The control experiments indicated that the N-oxide moiety of the substrates played a critical ro ...[more]

PMID: 29780567

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