On the origin of changes in topicity observed in Diels–Alder reactions catalyzed by Ti–TADDOLates
摘要:
New C-2 symmetric TADDOLs containing different groups at the 2-position of the dioxolane ring have been prepared. The Ti catalysts derived from these have been studied in the Diels-Alder reaction of cyclopentadiene and (E)-2-butenoyl-1,3-oxazolidin-2-one. Substituents at the C-2 position of the dioxolane ring can play an important role in determining the selectivity as well as the nature of the major isomer. This effect is more important for TADDOLs containing bulky aromatic groups such as 3,5-dimethylphenyl- or 1-naphthyl at the alpha -positions. Experimental evidence supports the hypothesis that pi-pi. interactions between aromatic groups at the C-2 and the ones at the a-positions are critical in this respect. (C) 2001 Elsevier Science Ltd. All rights reserved.
A compound and method for producing an enantiomerically enriched epoxide from an olefin using a chiral ketone and an oxidizing agent is disclosed.
一种化合物及其生产方法被披露,该方法使用手性酮和氧化剂从烯烃生产具有对映体富集的环氧乙烷。
Stepwise Reduction of Acetals to the Corresponding Hydrocarbons. A Mild and Effective Transformation via Carbinyl Bromides
作者:Takeshi Oriyama、Yuichi Ichimura、Gen Koga
DOI:10.1246/bcsj.64.2581
日期:1991.8
Stepwise reduction of two alkoxyl groups in acetal was effected by the action of triethylsilane along with acetyl bromide and SnBr2 and then of tributyltin hydride (or lithium aluminium hydride) providing methyl or methylene compounds in good yields under very mild conditions.
Highly Stereoselective Synthesis of <i>cis</i>-2-Substituted-3-vinyltetrahydrofurans from (<i>Z</i>)-Trimethyl(5-trimethylsiloxy-2-pentenyl)silane and Acetals
作者:Tomohumi Sano、Takeshi Oriyama
DOI:10.1055/s-1997-3261
日期:1997.6
A variety of cis-2-substituted-3-vinyltetrahydrofurans are easily and stereoselectively produced by the reaction of acetals with (Z)-trimethyl(5-trimethylsiloxy-2-pentenyl)silane under the influence of a catalytic amount of trimethylsilyl trifluoromethanesulfonate under very mild conditions.
Simple Method for the Preparation of Dimethyl Acetals from Ketones with Montmorillonite K 10 and p‐Toluenesulfonic Acid
作者:Horacio Mansilla、David Regás
DOI:10.1080/00397910600639315
日期:2006.6
Abstract A simple method for conversion of ketones to their corresponding dimethyl acetals using montmorillonite K 10 and p‐toluenesulfonic acid as acidic cocatalysts under very mild reaction conditions is described.
摘要描述了一种在非常温和的反应条件下使用蒙脱石 K 10 和对甲苯磺酸作为酸性助催化剂将酮转化为其相应二甲基缩醛的简单方法。
Development of a Tunable Chiral Pyridine Ligand Unit for Enantioselective Iridium-Catalyzed C–H Borylation
作者:Peidong Song、Linlin Hu、Tao Yu、Jiao Jiao、Yangqing He、Liang Xu、Pengfei Li
DOI:10.1021/acscatal.1c01671
日期:2021.6.18
Although pyridine derivatives are versatile supporting ligands in catalysis, the development of their chiral versions has been relatively limited. Herein, we report the design, synthesis, and proof-of-concept application of a structurally tunable chiral pyridine framework featuring an annulated compact ring system. Using an N,B-bidentate ligand skeleton containing the chiral pyridine moiety, we have