Catalytic Asymmetric Cyanosilylation of Ketones with Chiral Lewis Base
作者:Shi-Kai Tian、Ran Hong、Li Deng
DOI:10.1021/ja036222p
日期:2003.8.1
catalytic approaches for the enantioselective creation of quaternary stereocenters remains a highly desirable yet challenging goal. In this Communication, we describe a highlyenantioselective cyanosilylation of acetal ketones (alpha,alpha-dialkoxy ketones) catalyzed by modified cinchona alkaloids. This reaction is the first highlyenantioselective cyanosilylation of ketones catalyzed by an organic chiral
Enantioselective reactions of simple ketones, α,α‐ and β,β‐dialkoxy ketones, and α‐alkoxy ketones with trimethylsilyl cyanide catalyzed by the bimetallic systems of amino acid/BINAP/ruthenium(II) complexes and lithium phenoxide have been studied [BINAP=2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthyl]. The Ru(PhGly)2(BINAP)‐lithium phenoxide system showed high enantioselectivity for the reaction of acetophenone
Asymmetric Hydrogenation of Aromatic Ketones Catalyzed by the TolBINAP/DMAPEN−Ruthenium(II) Complex: A Significant Effect of <i>N</i>-Substituents of Chiral 1,2-Diamine Ligands on Enantioselectivity
mode of enantioface selection was interpreted by using transition state models based on the X-ray structure of the catalyst precursor. The chiral catalyst effected the hydrogenation of alkyl aryl ketones and arylglyoxal dialkyl acetals to afford the chiral alcohol in >99% ee in the best cases. Hydrogenation of racemic benzoin methyl ether with the chiral catalyst through dynamic kinetic resolution gave
One-pot synthesis of α-ketoacetals from aryl methyl ketones in the presence of selenous acid catalyzed by boron trifluoride etherate
作者:Icydora Kharkongor、Bekington Myrboh
DOI:10.1016/j.tetlet.2015.05.087
日期:2015.7
A simple and efficient one-pot preparation of α-ketoacetals from substituted acetophenones and triethylorthoformate in the presence of H2SeO3 and BF3·Et2O as catalyst has been developed. The desired products are obtained in good yields by a simple protocol involving neat and mild reaction conditions. The present methodology provides an attractive alternative method for the preparation of α-ketoacetal
开发了一种简单有效的一锅法,在H 2 SeO 3和BF 3 ·Et 2 O作为催化剂的情况下,由取代的苯乙酮和原甲酸三乙酯制备α-酮缩醛。通过涉及纯净的和温和的反应条件的简单方案以高收率获得所需产物。本方法提供了制备α-酮缩醛衍生物的有吸引力的替代方法。
Catalytic cyanosilylation of ketones using organic catalyst 1,1,3,3-tetramethylguanidine
3-Tetramethylguanidine acts as a highly effective catalyst for cyanosilylation of various ketones and aldehydes to the corresponding cyanohydrintrimethylsilylethers in up to 99% yield. The reaction proceeds smoothly with 0.1 mol % catalyst loading at 25 °C undersolvent-freeconditions.