第一个钼催化的芳基和烷基取代的支链烯丙碳酸酯的高度区域和对映选择性烯丙胺化反应已被开发出来。包括药物和复杂生物活性分子在内的多种胺类均成功进行了胺化,并具有优异的反应结果(产率高达 96%、>99% ee 和 >20:1 b/l)。该反应可以放大,并已应用于手性药物分子( S )-氯吡格雷(Plavix)的全合成。
The utility of hydroxylamines as nitrogen nucleophiles was investigated in the iridium-catalyzed regio- and enantioselective allylic substitution. Allylic substitution with hydroxylamines proceeded with good enantioselectivities by using the iridium-complex of bis(oxazolinyl)pyridine ligand. The good regio- and enantioselectivities were also achieved in the reaction with alkylamines, p-anisidine, and 4-methoxyphenol.
Iridium-Catalyzed, Asymmetric Amination of Allylic Alcohols Activated by Lewis Acids
作者:Yasuhiro Yamashita、Apsara Gopalarathnam、John F. Hartwig
DOI:10.1021/ja0730718
日期:2007.6.1
enantioselective amination of allylic alcohols with Lewis acid activators to form branched allylic amine products is reported. The reactions of arylamines, benzylic amines, and secondary aliphatic amines in the presence of Nb(OEt)5 as activator occurred with high regioselectivities and high enantioselectivities. These results led to the development of Ir-catalyzed reactions of allylic alcohol with arylamines
报道了烯丙醇与路易斯酸活化剂的直接、Ir 催化、区域和对映选择性胺化反应,形成支链烯丙胺产物。在 Nb(OEt)5 作为活化剂存在下,芳胺、苄胺和脂肪仲胺的反应具有高区域选择性和高对映选择性。这些结果导致了烯丙醇与芳胺和 BPh3 作为催化量的活化剂的 Ir 催化反应的发展。这些反应是烯丙醇对映选择性取代的罕见例子。它们是烯丙醇取代以从单取代烯丙醇产生支化取代产物以及烯丙醇与胺亲核试剂的对映选择性取代的特别不寻常的例子。
[GRAPHICS]The viability of the iridium complex of pybox as chiral catalyst in allylic substitutions and the enantiosilective synthesis of branched products was studied. Among several chiral ligands evaluated, the iridium complex of pybox having a phenyl group catalyzed the reaction with high activity to form the branched amines with good enantioselectivities when hydroxylamine, amine, and aniline were employed as a nucleophile. The allylic substitution with oximes proceeded smoothly to give the branched oxime ethers with good enantioselectivities.
Bicyclic Cyclopentenones via the Combination of an Iridium- Catalyzed Allylic Substitution with a Diastereoselective Intramolecular Pauson-Khand Reaction
作者:Andreas Farwick、Jens U. Engelhart、Olena Tverskoy、Carolin Welter、Quendolin A. Umlauf née Stang、Frank Rominger、William J. Kerr、Günter Helmchen
DOI:10.1002/adsc.201000706
日期:2011.2.11
Enantioselectivesyntheses of bicyclic cyclopentenones are described. Key steps are an iridium-catalyzedallylicsubstitution and an intramolecular diastereoselective Pauson–Khand reaction. The diastereoselectivity of the Pauson–Khand reaction was found to be crucially dependent on the unit connecting the propargylic and the olefinic parts of the precursor. Very high degrees of diastereoselection were