A New Catalyst for the Asymmetric Henry Reaction: Synthesis of β-Nitroethanols in High Enantiomeric Excess
作者:James D. White、Subrata Shaw
DOI:10.1021/ol3030023
日期:2012.12.21
has been designed and synthesized from cis-2,5-diaminobicyclo[2.2.2]octane. The complex generated in situ by the interaction of the ligand with (CuOTf)2·C6H5CH3 was an efficient catalyst for the asymmetric Henry reaction, producing nitroaldol products in high yield and good stereoselectivity. Henry reactions catalyzed by this tetrahydrosalen-Cu(I) complex led to syntheses of β-adrenergic blocking agents
从顺-2,5-二氨基双环[2.2.2]辛烷设计并合成了一种新的手性四氢salen配体。通过配体与(CuOTf)2 ·C 6 H 5 CH 3的相互作用原位生成的配合物是用于不对称亨利反应的有效催化剂,可以高收率和良好的立体选择性生产硝基醛醇产物。该四氢salen -Cu(I)配合物催化的亨利反应导致β-肾上腺素能阻断剂(S)-甲苯酚,(S)-莫普洛尔和(S)-丙醇的合成。
The hydroxynitrilelyase from Hevea brasiliensis not only catalyzes – according to the natural activity of this enzyme – the formation and cleavage of cyanohydrins but also the reaction of nitroalkanes with aldehydes (Henryreaction). This is the first example of an enzymatic nitroaldolreaction. With nitromethane and nitroethane a broad range of aldehydes can be transformed into the corresponding
2‐endo‐substituted and 2‐endo,N‐fused bi‐ and tricyclic bispidines. The new diamines were evaluated as the chiral ligands in asymmetricHenryreactions. Excellent enantioselectivities of up to 99 % ee and good diastereomeric ratios of up to 86:14 were reached with a copper(II) complex modified by a 2‐endo,N‐(3,3‐dimethylpyrrolidine)‐annelated bispidine. Its performance is superior to that of the well‐known bispidines