نتایج جستجو برای: claisen rearrangement

تعداد نتایج: 27614  

Journal: :Molecules 2008
Miroslava Martinková Jozef Gonda Jana Raschmanová Alexandra Novodomská Jozef Kozísek Lucia Perasinová

C-Glycosyl-(S)- and (R)-alanines 12a and 12b were synthesized from the known beta-C-glycoside 1. The nitrogen function was introduced by aza-Claisen rearrangement of the allylic thiocyanate 7, derived from the corresponding alcohol 6. The absolute configuration of the newly created chiral carbon center (C-3) was assigned by X-ray diffraction analysis of the intermediate 3(S)-isothiocyanato-D-gl...

2017
Marko Kljajic Johannes G Puschnig Hansjörg Weber Rolf Breinbauer

An additive-free Pd-catalyzed α-allylation of different imino-group-ontaining heterocycles is reported. The activation of α-CH pronucleophiles (pKa (DMSO) > 25) occurs without the addition of strong bases or Lewis acids using only the Pd/Xantphos catalyst system. The reaction scope has been studied for various 5- and 6-membered nitrogen-containing heterocycles (yields up to 96%). Mechanistic in...

Journal: :Organic letters 2010
Yong-Sil Lee Jong-Wha Jung Seok-Ho Kim Jae-Kyung Jung Seung-Mann Paek Nam-Jung Kim Dong-Jo Chang Jeeyeon Lee Young-Ger Suh

The first asymmetric total synthesis of fluvirucinine A(2) has been accomplished. A key feature of the synthesis is an iterative lactam ring expansion to provide rapid access to the 14-membered lactam skeleton and three stereogenic centers. The excellent remote control of the three stereogenic centers relied on stereoselective amidoalkylation followed by an amide-enolate-induced aza-Claisen rea...

Journal: :Journal of the American Chemical Society 2002
Tristan H Lambert David W C MacMillan

A new Lewis acid-catalyzed Claisen rearrangement has been developed that allows the stereoselective construction of beta-amino-alpha,beta,epsilon,zeta-unsaturated-gamma,delta-disubstituted esters from simple allylic amines and allenoate esters. This reaction, which is contingent upon the use of Lewis acid, can be conducted with a range of metal salts (Yb(OTf)3, AlCl3, Sn(OTf)2, Cu(OTf)2, MgBr2....

2017
Pamela T Wong Edward W Roberts Shengzhuang Tang Jhindan Mukherjee Jayme Cannon Alyssa J Nip Kaitlin Corbin Matthew F Krummel Seok Ki Choi

The use of coumarin caged molecules has been well documented in numerous photocaging applications including for the spatiotemporal control of Cre-estrogen receptor (Cre-ERT2) recombinase activity. In this article, we report that 4-hydroxytamoxifen (4OHT) caged with coumarin via a conventional ether linkage led to an unexpected photo-Claisen rearrangement which significantly competed with the re...

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