Copper(II) Acetate-Induced Oxidation of Hydrazones to Diazo Compounds under Flow Conditions Followed by Dirhodium-Catalyzed Enantioselective Cyclopropanation Reactions
Copper(II) Acetate-Induced Oxidation of Hydrazones to Diazo Compounds under Flow Conditions Followed by Dirhodium-Catalyzed Enantioselective Cyclopropanation Reactions
复制标题
乙酸铜 (II) 在流动条件下诱导腙氧化为重氮化合物，然后进行铑催化的对映选择性环丙烷化反应
DOI：
10.1021/acs.orglett.1c01580
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发表时间：
2021
期刊：
影响因子：
5.2
通讯作者：
Davies, Huw M.
中科院分区：
文献类型：
--
作者：
Wei, Bo;Hatridge, Taylor A.;Jones, Christopher W.;Davies, Huw M.
在铑催化环丙化反应中，建立了重氮化合物在线合成和下游消耗的串联系统。N-二甲氨基吡啶通过吸附Cu(OAc)2-H2O/N的硅胶柱，在流动中氧化腙生成芳基重氮乙酸酯。粗芳基重氮乙酸酯从该柱中洗脱后直接进入下游环丙化反应，由手性四羧酸二钠Rh2(R-p-Ph-TPCP)4和Rh2(R-PTAD)4催化。这种便捷的流动-间歇法以高产率和高水平的对映选择性合成了一系列1,2-二芳基环丙烷-1-羧酸酯。
A tandem system comprising in-line diazo compound synthesis and downstream consumption in a rhodium-catalyzed cyclopropanation reaction has been developed. Passing hydrazone through a silica column absorbed with Cu(OAc)2-H2O/N,N-dimethylaminopyridine oxidized the hydrazone to generate an aryldiazoacetate in flow. The crude aryldiazoacetate elutes from this column directly into a downstream cyclopropanation reaction, catalyzed by the chiral dirhodium tetracarboxylates, Rh2(R-p-Ph-TPCP)4and Rh2(R-PTAD)4. This convenient flow to batch method was applied to the synthesis of a range of 1,2-diarylcyclopropane-1-carboxylates in high yields and with high levels of enantioselectivity.