359001-86-8Relevant academic research and scientific papers
Stereoselective Synthesis of Trisubstituted Alkenes through Sequential Iron-Catalyzed Reductive anti-Carbozincation of Terminal Alkynes and Base-Metal-Catalyzed Negishi Cross-Coupling
Cheung, Chi Wai,Hu, Xile
, p. 18439 - 18444 (2015)
The stereoselective synthesis of trisubstituted alkenes is challenging. Here, we show that an iron-catalyzed anti-selective carbozincation of terminal alkynes can be combined with a base-metal-catalyzed cross-coupling to prepare trisubstituted alkenes in a one-pot reaction and with high regio- and stereocontrol. Cu-, Ni-, and Co-based catalytic systems are developed for the coupling of sp-, sp2-, and sp3-hybridized carbon electrophiles, respectively. The method encompasses a large substrate scope, as various alkynyl, aryl, alkenyl, acyl, and alkyl halides are suitable coupling partners. Compared with conventional carbometalation reactions of alkynes, the current method avoids pre-made organometallic reagents and has a distinct stereoselectivity. One-pot reaction: A wide range of trisubstituted olefins can be stereoselectively prepared by a sequential iron-catalyzed anti-carbozincation of terminal arylalkynes with alkyl iodides followed by copper-, nickel-, and cobalt-catalyzed cross-couplings with various sp-, sp2-, and sp3-carbon electrophiles, respectively (see scheme; DMA=dimethylacetamide, bipy=2,2-bipyridine, cod=1,5-cyclooctadiene, TMEDA=N,N,N′,N′-tetramethylethylenediamine).
Diastereoselective remote C-H activation by hydroboration
Varela, Jesus A.,Pena, Diego,Goldfuss, Bernd,Denisenko, Dmitri,Kulhanek, Jiri,Polborn, Kurt,Knochel, Paul
, p. 4252 - 4264 (2007/10/03)
Hydroboration of tetrasubstituted or trisubstituted alkenes with BH 3 and subsequent thermolysis allows remote diastereoselective C-H activation of neighboring aryl rings. Tetrasubstituted and trisubstituted 1,1-diphenyl-ethylene derivatives undergo a highly stereoselective 1,2-rearrangement followed by remote C-H activation to lead, after oxidative workup, to a diol in which the relative stereochemistry of two stereocenters has been controlled. The mechanism of this remote activation has been studied and extended to related molecules that undergo this stereoselective C-H activation, namely alkenylbiphenyl systems or alkenes with only one phenyl ring, such as alkenylbenzenes. or bicyclic systems. We have shown that this reaction allows diastereoselective synthesis of molecules with up to three contiguous chiral centers.
