The iridium/f-diaphos L1, L5 or L12 catalyzed asymmetric hydrogenation of 2-imidazolyl aryl/alkyl ketones to afford two enantiomers of the desired chiral alcohols with high conversions (up to 99% yield) and moderate to excellent enantioselectivities (61% - >99% ee) was realized for the first time. This protocol could be easily conducted on a gram-scale with a TON of 9700.
铱/ f-二磷L1、L5或L12催化 2-咪唑基芳基/烷基酮的不对称氢化,得到所需手性醇的两种对映异构体,具有高转化率(高达 99% 的产率)和中等至优异的对映选择性(61% - >99% ee ) 首次实现。该协议可以在 TON 为 9700 的克级上轻松执行。
Enantioselective Synthesis of (<i>R</i>)- and (<i>S</i>)-Cizolirtine; Application of Oxazaborolidine-Catalyzed Asymmetric Borane Reduction to Azolyl Phenyl Ketones
作者:Antoni Torrens、José A. Castrillo、Alex Claparols、Jordi Redondo
DOI:10.1055/s-1999-2712
日期:1999.6
An efficient enantioselective synthesis of (R)- and (S)-cizolirtine 1 is described. The key step of the procedure is the CBS-oxazaborolidine asymmetric reduction of phenyl pyrazolyl ketone 2. Related enantioselective reductions of several azolyl phenyl ketones are also reported.