91153-97-8Relevant academic research and scientific papers
Quaternary Stereogenic Centers through Enantioselective Heck Arylation of Acyclic Olefins with Aryldiazonium Salts: Application in a Concise Synthesis of (R)-Verapamil
Oliveira, Caio C.,Pfaltz, Andreas,Correia, Carlos Roque Duarte
supporting information, p. 14036 - 14039 (2016/01/25)
We describe herein a highly regio- and enantioselective Pd-catalyzed Heck arylation of unactivated trisubstituted acyclic olefins to provide all-carbon quaternary stereogenic centers. Chiral N,N ligands of the pyrimidine- and pyrazino-oxazoline class were developed for that purpose, providing the desired products in good to high yields with enantiomeric ratios up to >99:1. Both linear and branched substituents on the olefins were well-tolerated. The potential of this new method is demonstrated by the straightforward synthesis of several O-methyl lactols and lactones containing quaternary stereocenters, together with a concise enantioselective total synthesis of the calcium channel blocker verapamil.
C-quaternary vinylglycinols by metal-catalyzed cyclization of allylic bistrichloroacetimidates
Klimovica, Kristine,Grigorjeva, Liene,Maleckis, Ansis,Popelis, Juris,Jirgensons, Aigars
supporting information; experimental part, p. 2849 - 2851 (2012/02/05)
Bistrichloroacetimidates derived from 2-substituted but-2-ene-1,4-diols are transformed into 4-substituted 4-vinyloxazolines in high yields and excellent regioselectivities when Lewis acids AlCl3, FeCl3, TMSOTf, BF3OEt2, and AgBF4 are used as catalysts as well as with the Pd(PPh3)2Cl2/AgBF4 catalytic system. Lower regioselectivity is achieved with a neutral PdCl 2(MeCN)2 catalyst and this could be a consequence of a switch to a competitive but less selective reaction mechanism. It is demonstrated that 4-substituted 4-vinyloxazolines can be efficiently transformed to N-Boc-protected C-quaternary vinylglycinols in a one-pot procedure. Georg Thieme Verlag Stuttgart · New York.
A NEW SYNTHESIS OF trans-2-SUBSTITUTED-2-BUTENE-1,4-DIOLS FROM 2-BUTYNE-1,4-DIOL VIA NUCLEOPHILIC ADDITION OF GRIGNARD REAGENTS
Ishino, Yoshio,Wakamoto, Kohji,Hirashima, Tsuneaki
, p. 765 - 768 (2007/10/02)
trans-2-Substituted-2-butene-1,4-diols were readily obtained by reactions of 2-butyne-1,4-diol with Grignard reagents in good yields.
