Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan.
Org Biomol Chem. 2011 Nov 7;9(21):7411-9. doi: 10.1039/c1ob06067h. Epub 2011 Sep 7.
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.
我们研究了在催化量的三甲基硅基三氟甲磺酸存在下，2-三甲硅氧基呋喃与 L-古洛糖衍生的手性硝酮的立体选择性乙烯基曼尼希反应。选择性强烈受硝酮的 C-取代基的体积影响：例如，C-苄氧基甲基硝酮生成了四个立体异构体，而大体积的 C-[(4S)-2,2-二甲基-1,3-二氧戊环-4-基]硝酮仅生成单一立体异构体。后者产物经过精心合成，得到了多氧霉素 C 和双异戊烯基海罂粟碱的关键合成中间体。
