Cobalt-Catalyzed Negishi Cross-Coupling Reactions of (Hetero)Arylzinc Reagents with Primary and Secondary Alkyl Bromides and Iodides
作者:Jeffrey M. Hammann、Diana Haas、Paul Knochel
DOI:10.1002/anie.201411960
日期:2015.4.7
di(hetero)arylzinc reagents with primary and secondaryalkyliodides or bromides using THF‐soluble CoCl2⋅2 LiCl and TMEDA as a ligand, which leads to the corresponding alkylated products in up to 88 % yield. A range of functional groups (e.g. COOR, CN, CF3, F) are tolerated in these substitution reactions. Remarkably, we do not observe rearrangement of secondaryalkyliodides to unbranched products. Additionally
Cobalt-Catalyzed Diastereoselective Cross-Couplings between Alkynylzinc Pivalates and Functionalized Cyclic Iodides or Bromides
作者:Lucie Thomas、Ferdinand H. Lutter、Maximilian S. Hofmayer、Konstantin Karaghiosoff、Paul Knochel
DOI:10.1021/acs.orglett.8b00784
日期:2018.4.20
Various 1,2-, 1,3-, and 1,4-substituted cyclic iodides or bromides undergo highly diastereoselective cross-couplings (diastereoselectivity (dr) up to 99:1) with a range of alkynylzinc pivalates, using CoCl2 (20 mol %) and trans-N,N,N',N'-tetramethylcyclohexane-1,2-diamine as a catalytic system.
Cobalt-Mediated Diastereoselective Cross-Coupling Reactions between Cyclic Halohydrins and Arylmagnesium Reagents
作者:Jeffrey M. Hammann、Andreas K. Steib、Paul Knochel
DOI:10.1021/ol503361m
日期:2014.12.19
Cyclic TBS-protected iodohydrins (and bromohydrins) undergo a highly diastereoselective cross-coupling with various aryl- and heteroarylmagnesium reagents in the presence of THF-soluble CoCl2.2LiCl and TMEDA as a ligand leading to trans-2-arylcyclohexanol derivatives in good yields and dr up to >99:1. A range of functional groups are tolerated in the Grignard reagent (e.g., COOR, CN, CF3, SF5). The use of heterocyclic iodohydrins leads to trans-3,4-disubstituted pyrrolidines and tetrahydrofurans.