Facile preparation of a new BINAP-based building block, 5,5'-diiodoBINAP, and its synthetic application.
Facile preparation of a new BINAP-based building block, 5,5'-diiodoBINAP, and its synthetic application.
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DOI：
10.1021/jo0517186
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发表时间：
2005-10
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影响因子：
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通讯作者：
Toyoshi Shimada;M. Suda;Toyohiro Nagano;K. Kakiuchi
中科院分区：
文献类型：
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作者：
Toyoshi Shimada;M. Suda;Toyohiro Nagano;K. Kakiuchi
[反应：见文]用二（吡啶）四氟硼酸碘成功地进行了BINAP二氧化的区域选择性碘化，得到5,5'-二碘BINAP二氧化，产率达到92%，未观察到形成4,4'-二碘BINAP二氧化。用Sonogashira交叉偶联反应与5,5'-二碘binap二氧化得到了所需的二（三甲基硅乙基）产品，收率为86%。得到的5,5'-二取代BINAP二氧化物被还原为相应的膦，作为手性配体用于铑催化苯硼酸与2-环己酮的不对称1,4加成得到3-苯基环己酮，收率高，对映选择性高。
[reaction: see text] Bis(pyridine)iodonium tetrafluoroborate was successfully used for regioselective iodination of BINAP dioxide to give 5,5'-diiodoBINAP dioxide in an excellent yield of 92%, with no observed formation of 4,4'-diiodoBINAP dioxide. A Sonogashira cross-coupling reaction with 5,5'-diiodoBINAP dioxide gave the desired bis(trimethylsilylethynyl) product in 86% yield. The resulting 5,5'-disubstituted BINAP dioxides were reduced to the corresponding phosphines, which were used as chiral ligands for rhodium-catalyzed asymmetric 1,4-addition of phenylboronic acid to 2-cyclohexenone to give 3-phenylcyclohexanone in excellent yield with high enantioselectivity.