Exploring the versatility of the Johnson–Claisen rearrangement: access to functionally versatile δ-ethoxycarbonyl-α,β-unsaturated nitriles
作者:Kelly L. Cosgrove、Ross P. McGeary
DOI:10.1016/j.tet.2010.02.045
日期:2010.4
aldehydes were converted to cyanohydrins, by employing either KCN in aqueous acid, or by using TMSCN with catalytic K2CO3, followed by acid hydrolysis of the TMS ether. These cyanohydrins underwent a Claisenrearrangement employing a modified Johnson–Claisen protocol to yield unsaturated nitriles in good yields and with moderate E/Z selectivity.
描述了实际进入δ-乙氧基羰基-α,β-不饱和腈的方法。通过在酸性水溶液中使用KCN或通过将TMSCN与催化性K 2 CO 3一起使用,然后将TMS醚酸水解,可以将α,β-不饱和醛转化为氰醇。这些氰醇经过改良的Johnson-Claisen方案进行了Claisen重排,以高收率和适度的E / Z选择性产生不饱和腈。
Kinetic Resolution of Racemic Amino Alcohols through Intermolecular Acetalization Catalyzed by a Chiral Brønsted Acid
作者:Takuto Yamanaka、Azusa Kondoh、Masahiro Terada
DOI:10.1021/ja512238n
日期:2015.1.28
The kineticresolution of racemic secondary alcohols is a fundamental method for obtaining enantiomerically enriched alcohols. Compared to esterification, which is a well-established method for this purpose, kineticresolution through enantioselective intermolecular acetalization has not been reported to date despite the fact that the formation of acetals is widely adopted to protect hydroxy groups
Catalytic electronic activation: indirect Sharpless asymmetric epoxidation of enals
作者:Phillip J Black、Kerry Jenkins、Jonathan M.J Williams
DOI:10.1016/s0957-4166(02)00100-3
日期:2002.3
The asymmetricepoxidation of allylic cyanohydrins using the Sharpless kinetic resolution (SKR) reaction was explored. The SKR methodology was extended to enals via in-situ conversion into the corresponding cyanohydrin. The prospect of achieving a dynamic Sharpless kinetic resolution was investigated and the enantioselectivity of the SKR of (E)-2-hydroxy-3-methyl-4-phenyl-3-butenenitrile 1 studied