Impact on Hydrogenation Catalytic Cycle of the R Groups’ Cyclic Feature in “R-SMS-Phos”
摘要:
A series of R-SMS-Phos ligands was evaluated in the Rh(I)-catalyzed hydrogenation of a set of olefins showing a marked influence of the cyclic nature and structure of the R groups. Overall, cPen- and Cy-SMS-Phos performed efficiently, while Ph- and Bn-SMS-Phos exhibited slower kinetics and furnished lower ee's also compared with C6F5CH2-SMS-Phos. The Rh(I)-(Cy-SMS-Phos) catalyst was screened under mild conditions displaying excellent enantioselectivities and high TOFs. Cases of catalysis under catalyst or substrate control were identified.
Reaction of acetals with aliphatic nitro compounds. Communication 4. Reaction of aliphatic andalicyclic ketals with nitroacetic acid ester and synthesis of ?,?-dehydro-?-acetylamino acid esters
Catalytic Asymmetric Hydrogenation of<b><i>α</i></b>-(Acetamido)acrylates Using TRAP Trans-Chelating Chiral Bisphosphine Ligands: Remarkable Effects of Ligand<b><i>P</i></b>-Substituent and Hydrogen Pressure on Enantioselectivity
作者:Ryoichi Kuwano、Masaya Sawamura、Yoshihiko Ito
DOI:10.1246/bcsj.73.2571
日期:2000.11
β-substituent and the ligand P-substituent as well as decreasing hydrogen pressure. The selectivity for the (R)-product in the reaction with EtTRAP-rhodium catalyst at 60 °C and 0.5 kg cm-2 of hydrogen pressure was as follows: R = H, 96% ee; R = Me, 92% ee; R = Ph, 77% ee; R = i-Pr, 57% ee. The remarkable steric and pressure effects caused a dramatic reversal of enantioselectivity in the reaction of methyl
用 [Rh(cod)2]BF4 和反式螯合手性双膦配体 (S,S)-2,2'-双 [( R)-1-(二烷基膦基)乙基]-1,1'-二茂铁[(R,R)-(S,S)-TRAPs]。在β-未取代或β-单取代的α-(乙酰氨基)丙烯酸酯[(E)-RCH=C(NHAc)CO2Me]的反应中,(R)-氢化产物的选择性随着底物β-空间需求的降低而增加取代基和配体 P 取代基以及降低氢压。在 60 °C 和 0.5 kg cm-2 氢气压力下与 EtTRAP-铑催化剂反应的 (R)-产物的选择性如下:R = H,96% ee;R = Me,92% ee;R = Ph,77% ee;R = i-Pr,57% ee。显着的空间和压力效应导致 2-(N-乙酰氨基) 肉桂酸甲酯 (R = Ph) 反应中对映选择性的显着逆转。例如,在 60 °C 和 0.1 kg cm-2 氢气压力下使用 EtTRAP 的选择性为 87%
Application of Chiral Mixed Phosphorus/Sulfur Ligands to Enantioselective Rhodium-Catalyzed Dehydroamino Acid Hydrogenation and Ketone Hydrosilylation Processes
作者:David A. Evans、Forrest E. Michael、Jason S. Tedrow、Kevin R. Campos
DOI:10.1021/ja012639o
日期:2003.3.1
Rh-catalyzed dehydroamino acid hydrogenation and ketone hydrosilylation reactions (eqs 1, 2). After assaying the influence of the substituents at sulfur, the substituents on the ligand backbone, the relative stereochemistry within the ligand backbone, and the substituents at phosphorus, ligands 2c (R = 3,5-dimethylphenyl) and 3 were found to be optimal in the Rh-catalyzed hydrogenation of a variety of alpha-acylaminoacrylates
BisP* moieties as ligands revealed extremely high enantioselectivities − 99% (9b) and 98% (9e) − when the trisubstituted and tetrasubstituted dehydro-α-amino acid derivatives 8b and 8e, respectively, were used as substrates. It was found that unsymmetrical BisP* species tended to exhibit higher enantioselectivity than C2-symmetrical BisP* species in the Rh-catalyzedhydrogenation of (Z)-dehydro-β-amino
[DE] FERROCENYL-1, 2-DIPHOSPHINE, DEREN HERSTELLUNG UND DEREN VERWENDUNG<br/>[EN] FERROCENYL-1, 2-DIPHOSPHINES, THE PRODUCTION THEREOF AND THEIR USE<br/>[FR] FERROCENYL-1, 2-DIPHOSPHINES, LEUR PREPARATION ET LEUR UTILISATION
申请人:SOLVIAS AG
公开号:WO2005056568A1
公开(公告)日:2005-06-23
Verbindungen der Formel (I) in Form von Racematen, Gemischen von Diastereomeren oder im wesentlichen reinen Diastereomeren, worin R1 ein Wasserstoffatom oder C1-C4-Alkyl bedeutet, und wenigstens ein Sekundärphosphin eine unsubstituierte oder substituierte zyklische Phosphingruppe darstellt, oder deren Phosphoniumsalze mit ein oder zwei monovalenten Anionen oder einem divalenten Anion. Die Verbindungen der Formel (I) werden über ein neues Verfahren zugänglich und sind wertvolle Liganden für katalytisch wirksame Metallkomplexe in der asymmetrischen Synthese.
Formula (I)的连接形式,以拉克米形式、二对异构体混合物或基本纯的二对异构体形式存在,其中R1代表氢原子或C1-C4烷基,至少一种次磷酸酯是未取代或取代的环状磷基,或其磷酸铵盐具有一个或两个一价阴离子或一个二价阴离子。Formula (I)的化合物通过一种新方法可获得,并且它们是用于不对称合成中的具有催化活性的金属配合物的宝贵配体。
Heavyweight “R-SMS-Phos” Ligands in the Olefins’ Hydrogenation Arena
作者:Borut Zupančič、Barbara Mohar、Michel Stephan
DOI:10.1021/ol100184p
日期:2010.3.19
A series of enantiopure P-stereogenic 1,2-bis[(o-RO-phenyl)(phenyl)phosphino]ethane (R-SMS-Phos) ligands wherein R= i-Pr, i-Bu, t-Bu, 3-Pen, and CH2TMS was assessed in the Rh(I)-catalyzed hydrogenation of an indicative set of olefins. The best performing t-Bu-SMS-Phos ligand was screened against a wide range of representative classes of standard and new olefinic substrates such as dehydroamido esters
一系列对映纯的P-立体异构1,2-双[(o -RO-苯基)(苯基)膦基]乙烷(R-SMS-Phos)配体,其中R = i -Pr,i -Bu,t -Bu,3 -苯和CH 2 TMS是在Rh(I)催化的一组指示性烯烃的氢化反应中评估的。表现最佳吨-Bu-SMS-PHOS配体筛选对宽范围的代表类标准和新的烯烃底材如dehydroamido酯,脱氢α酰氨基膦酸酯,烯酰胺,衣康酸酯,丙烯酸酯,乙烯醇的,α-苯甲酸磷新戊酯,α-(2-吡啶基N-氧化物)苯乙烯和α-(1-羟亚氨基乙基)苯乙烯。在温和的条件下可获得出色的对映选择性和高TOF。