Organic & Biomolecular Chemistry 2011-11-07

Stereoselective vinylogous Mannich reaction of 2-trimethylsilyloxyfuran with N-gulosyl nitrones.

Osamu Tamura, Kodai Takeda, Naka Mita, Masanori Sakamoto, Iwao Okamoto, Nobuyoshi Morita, Hiroyuki Ishibashi

Index: Org. Biomol. Chem. 9(21) , 7411-9, (2011)

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Abstract

Stereoselective vinylogous Mannich reaction of 2-trimethylsilyloxyfuran with L-gulose-derived chiral nitrones in the presence of a catalytic amount of trimethylsilyl trifluoromethanesulfonate was investigated. The selectivity was strongly influenced by the bulkiness of the C-substituent of the nitrone: for example, C-benzyloxymethyl nitrone afforded four stereoisomers, whereas bulky C-[(4S)-2,2-dimethyl-1,3-dioxolan-4-yl]nitrone gave a single stereoisomer. The latter product was elaborated to afford key synthetic intermediates for polyoxin C and dysiherbaine.