描述了C 2对称的手性O,N,N,O-四齿2,2-联吡啶二醇二醇丙烷配体的合成。Mukaiyama–Michael反应被用作合成2,2-联吡啶丙烷9的重要反应。在合成的配体中,配体11在二乙基锌和各种醛类化合物中均表现出出色的手性诱导(至多97%ee)。对于本催化体系,不需要在二乙基锌加成反应中使用额外的路易斯酸,例如Ti(O i Pr)4。
Chiral 2-(2-hydroxyaryl)alcohols (HAROLs) with a 1,4-diol scaffold as a new family of ligands and organocatalysts
作者:Ömer Dilek、Mustafa A. Tezeren、Tahir Tilki、Erkan Ertürk
DOI:10.1016/j.tet.2017.11.054
日期:2018.1
Efficient and modular syntheses of chiral 2-(2-hydroxyaryl)alcohols (HAROLs), novel 1,4-diols carrying one phenolic and one alcohol hydroxyl group, have been developed which led to generation of a small library of structurally diverse HAROLs in enantiomerically pure form. Of the different HAROLs examined, a HAROL based on the indan backbone exhibited the highest activity and enantioselectivity in the
高效和模块化的手性2-(2-羟基芳基)醇(HAROLs)的合成,带有一个酚和一个醇羟基的新型1,4-二醇已被开发出来,这导致在对映异构体中生成结构多样的HAROLS小文库纯形式。在考察的不同HAROL中,基于茚满骨架的HAROL在Ti(O i Pr)4(y高达97%, 88%ee)并在三田膦的促进下在Morita-Baylis-Hillman反应中作为氢键供体有机催化剂发挥作用。
Polystyrene-Supported (2<i>S</i>)-(−)-3-<i>exo</i>-Piperazinoisoborneol: An Efficient Catalyst for the Batch and Continuous Flow Production of Enantiopure Alcohols
作者:Laura Osorio-Planes、Carles Rodríguez-Escrich、Miquel A. Pericàs
DOI:10.1021/ol300415f
日期:2012.4.6
(PS-PIB) of 3-exo-morpholinoisoborneol (MIB), designed for increased chemical stability, has been synthesized and used as a ligand in the asymmetric alkylation of aldehydes with Et2Zn. The supportedligand turned out to be highly active and enantioselective for a broad scope of substrates (92–99% ee), allowing repeated recycling. A single-pass, continuousflow process implemented with PS-PIB shows only
Switching of Enantioselectivity in the Catalytic Addition of Diethylzinc to Aldehydes by Regioisomeric Chiral 1,3-Amino Sulfonamide Ligands
作者:Takuji Hirose、Kazuyuki Sugawara、Koichi Kodama
DOI:10.1021/jo200834n
日期:2011.7.1
Twenty chiral 1,3-amino sulfonamides of two classes (2a–i and 3a–k) have been prepared from (−)-cis-2-benzamidocyclohexanecarboxylic acid (1) and studied as ligands for catalytic enantioselectiveaddition of Et2Zn to a variety of aromatic and aliphatic aldehydes. The ligands 2 and 3 are regioisomers in which the position of the amine and sulfonamide groups is exchanged. Each class of ligands with the
d-Penicillamine derived thiazolidine ligands were prepared in a two-step synthetic sequence and used in the enantioselective alkylation of a variety of aromatic aldehydes with diethylzinc at room temperature. Excellent ee, up to >99%, and nearly complete conversions were observed. Structurally analogous l-cysteine derived thiazolidine ligands were also synthesized and tested for comparative purposes
Synthesis of Chiral Pyridylphenols for the Enantioselective Addition of Diethylzinc to Aldehydes
作者:Pei-Shan Wu、Chinpiao Chen
DOI:10.1002/jccs.201100474
日期:2012.6
Chiral 8‐substituted 2‐(8,10,10‐trimethyl‐6‐aza‐tricyclo[7.1.1.02,7]undeca‐2(7),3,5‐trien‐5‐yl)‐phenols were prepared from a high enantiopurity (>97% ee) of (1R)‐(+)‐α‐pinene, and assessed in the enantioselectiveaddition of diethylzinc to substituted benzaldehydes, giving the (S)‐alcohols with enantiomeric excess ranging from 33% to 89%. Interestingly, in all cases, except for those of ortho‐chlorobenzaldehyde