mercuration of calix[4]arene immobilized in the cone conformation allowed the introduction of an amino group at the meta position of the basic skeleton. Acylation and subsequent intramolecular Bischler–Napieralski-type cyclization led to a novel type of bridged calixarene containing a seven-membered ring. These compounds with an enlarged and rigidified cavity represent a unique and inherentlychiral system
3-Aminoquinazoline–phosphine ligands and their ruthenium(II) complexes: application in catalytic hydrogenation and transfer hydrogenation reactions
作者:Mustafa Kemal Yılmaz、Mustafa Keleş
DOI:10.1007/s11243-018-0213-9
日期:2018.4
and microanalysis. The 3-aminoquinazolinone–phosphine ligands were found to coordinate with the Ru(II) center via their phosphorus and nitrogen atoms. The Ru(II) complexes were applied as catalysts for the hydrogenation and transferhydrogenation of prochiral ketones. The results showed that these complexes are efficient transferhydrogenation catalysts.
Asymmetrische Synthesen über heterocyclische Zwischenstufen, XVI. Enantioselektive Synthese von α-Alkyl-α-phenylglycinen durch Alkylieren von an C-6 chiral substituierten 3,6-Dihydro-3-phenyl-2H-1,4-oxazin-2-onen
作者:Wolfgang Hartwig、Ulrich Schöllkopf
DOI:10.1002/jlac.198219821105
日期:1982.11.22
Ausgehend von DL-Phenylglycin und (S)-2-Hydroxyalkansäuren 4 werden die 3,6-Dihydro-3-phenyl-2H-1,4-oxazin-2-one 3 aufgebaut, die an C-6 ein endocyclisches Chiralitätszentrum besitzen. Die Anionen 10 von 3 reagieren mit Alkylhalogeniden an C-3 mit guten chemischen Ausbeuten und mit 50 bis mehr als 95% d. e. (asymmetrische Induktion). Bei der Hydrolyse der Addukte 11 werden die 2-Hydroxyalkansäuren
从DL-苯基甘氨酸和(S)-2-羟基链烷酸4开始,构建了3,6-二氢-3-苯基-2 H -1,4-恶嗪-2-酮3,它们的内环中心为C-6的手性。阴离子10的3与烷基卤化物反应,在C-3具有良好的化学产率,并用50至95%以上的德(不对称诱导)。在加合物11的水解过程中,释放出2-羟基链烷酸4和旋光的(S)-α-烷基-α-苯基甘氨酸14。
The Synthesis of Chiral α-Aryl α-Hydroxy Carboxylic Acids via RuPHOX-Ru Catalyzed Asymmetric Hydrogenation
作者:Huan Guo、Jing Li、Delong Liu、Wanbin Zhang
DOI:10.1002/adsc.201700846
日期:2017.10.25
A ruthenocenyl phosphino‐oxazoline‐ruthenium complex (RuPHOX−Ru) catalyzedasymmetrichydrogenation of α‐aryl keto acids has been successfully developed, affording the corresponding chiral α‐aryl α‐hydroxy carboxylic acids in high yields and with up to 97% ee. The reaction could be performed on a gram scale with a relatively low catalyst loading (up to 5000 S/C) and the resulting products can be transformed
已成功开发了钌烯基膦基-恶唑啉-钌络合物(RuPHOX-Ru)催化的α-芳基酮酸不对称氢化反应,可提供高收率和ee高达97%的相应手性α-芳基α-羟基羧酸。该反应可以在相对较低的催化剂负载量(至多5000 S / C)下以克为单位进行,所得产物可以转化为几种手性结构单元,生物活性化合物和手性药物。
Synthesis of the C(1)–C(16) fragment of bryostatins using an ‘ene’ reaction between an allylsilane and an alkynone
作者:Matthew O’Brien、Eric J. Thomas
DOI:10.1016/j.tet.2011.09.064
日期:2011.12
mediated ‘ene’ reaction between (4R)-4,5-bis-(tert-butyldimethylsilyloxy)-2-(trimethylsilylmethyl)pent-1-ene (43) and (5S,7R,9S)-5,11-dibenzyloxy-4,4-dimethyl-7,9-dihydroxy-7,9-O-isopropylideneundec-1-yn-3-one (53) gave the (E)-vinylsilane 54 with excellent stereoselectivity. Simultaneous deprotection and cyclisation via a stereoselective oxy-Michael reaction gave the bicyclicacetal 57 after treatment