Regiodivergent reductive coupling of 2-substituted dienes to formaldehyde employing ruthenium or nickel catalyst: hydrohydroxymethylation via transfer hydrogenation
Regiodivergent reductive coupling of 2-substituted dienes to formaldehyde employing ruthenium or nickel catalyst: hydrohydroxymethylation via transfer hydrogenation
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DOI：
10.1039/c3sc22051f
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发表时间：
2013-01-01
期刊：
影响因子：
8.4
通讯作者：
Krische, Michael J.
中科院分区：
文献类型：
--
作者：
Koepfer, Alexander;Sam, Brannon;Krische, Michael J.
分别使用基于镍、阳离子钌和中性钌的金属催化剂实现了多聚甲醛在C1、C2和C3位上与2-取代二烯的区域选择性还原偶联。虽然 C1 加合物主要使用二烯，但硅或锡取代的二烯表现出 C4 区域选择性 - 这是首次在 2-取代丁二烯与醛的偶联中观察到这种区域选择性。镍和钌催化的工艺分别使用多聚甲醛或异丙醇，避免自燃或质量密集型还原剂。这些偶联可被视为二烯加氢甲酰化的替代方案，其结构异构产物的区域选择性形成尚未实现。
The regioselective reductive coupling of paraformaldehyde to 2-substituted dienes at positions C1, C2 and C3 was achieved using metal catalysts based on nickel, cationic ruthenium and neutral ruthenium, respectively. Whilst C1 adducts predominate using dienes, silicon- or tin-substituted dienes exhibit C4 regioselectivity - the first time that this regioselectivity has been observed for the coupling of 2-substituted butadienes to aldehydes. Both nickel- and ruthenium-catalyzed processes avoid pyrophoric or mass intensive reducing agents, using paraformaldehyde or isopropanol, respectively. These couplings may be viewed as alternatives to diene hydroformylation, for which regioselective formation of constitutionally isomeric products has not yet been achieved.