Diastereoconvergent Negishi Cross-Coupling Using Functionalized Cyclohexylzinc Reagents
摘要:
Highly diastereoselective Pd-catalyzed cross-coupling reactions of functionalized 2-, 3-, and 4-substituted cyclohexylzinc reagents with aryl, heteroaryl, and alkenyl iodides have been performed under mild conditions. The use of Ruphos (2-dicyclohexylphosphino-2',6'-diisopropoxybiphenyl) as a ligand as well as LiCl and N-ethylpyrrolidone (NEP) as additives leads to especially high diastereoselectivities and displays good functional group tolerance. The stereoselectivity can be explained by assuming that the intermediate palladium moiety occupies an equatorial position of the cyclohexyl ring.
Diastereoconvergent Negishi Cross-Coupling Using Functionalized Cyclohexylzinc Reagents
摘要:
Highly diastereoselective Pd-catalyzed cross-coupling reactions of functionalized 2-, 3-, and 4-substituted cyclohexylzinc reagents with aryl, heteroaryl, and alkenyl iodides have been performed under mild conditions. The use of Ruphos (2-dicyclohexylphosphino-2',6'-diisopropoxybiphenyl) as a ligand as well as LiCl and N-ethylpyrrolidone (NEP) as additives leads to especially high diastereoselectivities and displays good functional group tolerance. The stereoselectivity can be explained by assuming that the intermediate palladium moiety occupies an equatorial position of the cyclohexyl ring.
Cross-Coupling of Nonactivated Primary and Secondary Alkyl Halides with Aryl Grignard Reagents Catalyzed by Chiral Iron Pincer Complexes
作者:Xile Hu、Gerald Bauer、Chi Cheung
DOI:10.1055/s-0034-1380136
日期:——
Abstract Iron(III) bisoxazolinylphenylamido (bopa) pincer complexes are efficient precatalysts for the cross-coupling of nonactivated primary and secondary alkyl halides with phenyl Grignardreagents. The reactions proceed at room temperature in moderate to excellent yields. A variety of functional groups can be tolerated. The enantioselectivity of the coupling of secondary alkyl halides is low. Iron(III)
Mild and Phosphine-Free Iron-Catalyzed Cross-Coupling of Nonactivated Secondary Alkyl Halides with Alkynyl Grignard Reagents
作者:Chi Wai Cheung、Peng Ren、Xile Hu
DOI:10.1021/ol501087m
日期:2014.5.2
cross-coupling of nonactivated secondary alkylbromides and iodides with alkynyl Grignardreagents at room temperature has been developed. A wide range of secondary alkyl halides and terminal alkynes are tolerated to afford the substituted alkynes in good yields. A slight modification of the reaction protocol also allows for cross-coupling with a variety of primary alkyl halides.
Synthesis of <i>E</i>-Alkyl Alkenes from Terminal Alkynes via Ni-Catalyzed Cross-Coupling of Alkyl Halides with B-Alkenyl-9-borabicyclo[3.3.1]nonanes
作者:Thomas Di Franco、Alexandre Epenoy、Xile Hu
DOI:10.1021/acs.orglett.5b02482
日期:2015.10.2
The first Ni-catalyzed Suzuki–Miyaura coupling of alkyl halides with alkenyl-(9-BBN) reagents is reported. Both primary and secondary alkyl halides including alkylchlorides can be coupled. The coupling method can be combined with hydroboration of terminal alkynes, allowing the expedited synthesis of functionalized alkyl alkenes from readily available alkynes with complete (E)-selectivity in one pot
作者:Pablo M. Perez Garcia、Thomas Di Franco、Alessio Orsino、Peng Ren、Xile Hu
DOI:10.1021/ol302067b
日期:2012.8.17
A nickel pincer complex is found to catalyze alkyl-alkyl Kumada coupling reactions of 1,3- and 1,4-substituted cyclohexyl halides and tetrahydropyrans with an excellent diastereoselectivity. The mechanistic investigation of the coupling reactions provides evidence that the activation of alkyl halides is reversible.