Nucleophile Generation via Decarboxylation: Asymmetric Construction of Contiguous Trisubstituted and Quaternary Stereocenters through a Cu(I)-Catalyzed Decarboxylative Mannich-Type Reaction
作者:Liang Yin、Motomu Kanai、Masakatsu Shibasaki
DOI:10.1021/ja9036675
日期:2009.7.22
first catalytic asymmetric decarboxylative Mannich-type reaction between aldimines and cyanocarboxylic acids was developed. Alpha,alpha,beta-trisubstituted beta-amino nitriles containing contiguous trisubstituted and all-carbon quaternary stereocenters were produced with moderate to high enantio- and diastereoselectivity using 5 mol % CuOAc-(R)-DTBM-SEGPHOS complex as an asymmetric catalyst. This reaction
The synthesis and stereospecific solid-state photodecarbonylation of hexasubstituted meso- and d,l-ketones
作者:Saori Shiraki、Arunkumar Natarajan、Miguel A. Garcia-Garibay
DOI:10.1039/c1pp05080j
日期:2011.9
Tertiary carbanions were trapped with half an equivalent of diphosgene to give meso- and d,l-hexasubstituted ketones in moderate yields and modest diastereoselectivities. The ketones were also synthesized by a step-wise synthesis in which the carbonyl group was first installed as an acid before activation and the second nucleophilic attack. This second method gave lower yields but similar diastereoselectivites
Acylanilide, 1. Mitt.: Synthese der Racemate und Enantiomere chiraler Acylanilide
作者:Joachim Knabe、Peter Christensen
DOI:10.1002/ardp.19883210215
日期:——
Durch Umsetzung der racem. und optischaktiven Cyanessigsäurechloride 1–4 (R = Cl) oder der Cyanessigsäuren 1–4 (R = OH) unter Zusatz von DCC mit p‐Phenetidin bzw. 4‐Hydroxyanilin wurde eine Reihe von racem. und optischaktiven Cyano‐Acylaniliden synthetisiert. Reaktion der Acylanilide 1a und 3a mit alkalischem Wasserstoffperoxid ergab die Malonsäuremonoamid‐anilide 1c und 3c; das Cyanoacylanilid 2a
Racem. und optisch aktive Hydantoine aus disubstituierten Cyanessigsäuren
作者:Joachim Knabe、Wolfgang Wunn
DOI:10.1002/ardp.19803130609
日期:——
Ausgehend von den chiralen disubstituierten Cyanessigsäuren 1 werden über die Isocyanate 3 die Racemate und einige Enantiomere der 5,5‐disubstituierten Hydantoine 6 undder 3‐Methylhydantoine 7 synthetisiert. Ihre absoluteKonfiguration wird abgeleitet.
Compounds of formulae (IA) and (IB):
1
wherein R
1
, R
2
, R
3
, Ar
1
and X are as defined above, are endothelin antagonists. The compounds are therefore useful in the treatment of a variety of conditions mediated by endothelin, such as restenosis, renal failure and systemic and pulmonary hypertension.