Non-Pd transition metal-catalyzed hydrostannations: Bu3SnF/PMHS as a tin hydride source
作者:Robert E. Maleczka、Banibrata Ghosh、William P. Gallagher、Aaron J. Baker、Jill A. Muchnij、Amy L. Szymanski
DOI:10.1016/j.tet.2013.02.064
日期:2013.5
and rhodium catalyzed alkyne hydrostannations using in situ generated Bu3SnH were studied. In most cases, Bu3SnF+polymethylhydrosiloxane (PMHS) performed well as the in situ source of Bu3SnH. In contrast, the combination of Bu3SnCl/KFaq/PMHS, which had witnessed earlier success in Pd-catalyzed hydrostannation reactions, proved less employable in alkyne hydrostannations mediated by these metals.
Rhodium complexes (RhClL3, RhCl(CO)L2, [RhCl(COD)]2; L=PPh3) catalyze hydrostannation of terminal acetylenes (RC≡CH; R=Ph, Me3Si, R1OC(R2)(R3), and R1OCH2CH2; R1=THP, OAc; R1, R2=H, Me) with Bu3SnH to produce R(Bu3Sn)C=CH2 selectively. Other transition metal complexes [MCl2L2(M=Ni, Pd, Pt, Co)] are also active for the hydrostannation, but with less selectivity.
Synthesis of variously 2-substituted alkyl (Z)- and (E)-2-alkenoates and (Z)- and (E)-α-ylidene-γ-butyrolactones via palladium-mediated cross-coupling reactions between organostannanes and organic halides
作者:Fabio Bellina、Adriano Carpita、Massimo De Santis、Renzo Rossi
DOI:10.1016/s0040-4020(01)89314-5
日期:1994.1
2-(1-alkenyl) as well as 2-acyl substituted α,β-unsaturatedesters, is based on the cross-coupling reaction between easily available alkyl (Z)- or (E)-2-halo-2-alkenoates and organostannanes in NMP, in the presence of catalytic amounts of PdCl2(PhCN)2, AsPh3 and CuI. (Z)-and (E)-2-ethenyl substituted α,β-unsaturatedesters prepared according to this procedure have been proven to be useful precursors to (Z)-
Asymmetric Addition of Alkenylstannanes to Alkylidene Meldrum’s Acids
作者:Stuart J. Mahoney、Aaron M. Dumas、Eric Fillion
DOI:10.1021/ol902216y
日期:2009.11.19
Herein, we describe enantioselective addition of alkenyltin reagents possessing a reactive and sensitive allylic functionality not readilyavailable to other classes of alkenyl metals. This method is enabled by the use of highlyelectrophilic alkylidene Meldrum’s acids as acceptors and a cationic Rh(I)−diene complex as catalyst.
Ligand effects on the stereochemistry of Stille couplings, as manifested in reactions of Z-alkenyl halides
作者:Guo-ping Lu、Karl R. Voigtritter、Chun Cai、Bruce H. Lipshutz
DOI:10.1039/c2cc33294a
日期:——
Unexpected losses in stereochemistry from Stille reactions involving Z-alkenyl halides have been shown to be ligand dependent. A new set of reaction conditions has been developed that, in most cases, leads to highly stereoselective cross-couplings under mild conditions, along with improved yields.