More Like this

1. Ni- and Pd-Catalyzed Enantioselective 1,2-Dicarbofunctionalization of Alkenes

   https://doi.org/10.1055/a-2108-9549  

   Kang, Taeho; Apolinar, Omar; Engle, Keary M (December 2023, Synthesis)

   Abstract Catalytic enantioselective 1,2-dicarbofunctionalization (1,2-DCF) of alkenes is a powerful transformation of growing importance in organic synthesis for constructing chiral building blocks, bioactive molecules, and agrochemicals. Both in a two- and three-component context, this family of reactions generates densely functionalized, structurally complex products in a single step. Across several distinct mechanistic pathways at play in these transformations with nickel or palladium catalysts, stereocontrol can be obtained through tailored chiral ligands. In this Review we discuss the various strategies, mechanisms, and catalysts that have been applied to achieve enantioinduction in alkene 1,2-DCF. 1 Introduction 2 Two-Component Enantioselective 1,2-DCF via Migratory Insertion 3 Two-Component Enantioselective 1,2-DCF via Radical Capture 4 Three-Component Enantioselective 1,2-DCF via Radical Capture 5 Three-Component Enantioselective 1,2-DCF via Migratory Insertion 6 Miscellaneous Mechanisms 7 Conclusion 

   more » « less
2. Directed, Nickel-Catalyzed 1,2-Alkylsulfenylation of Alkenyl Carbonyl Compounds

   https://doi.org/10.1039/D2SC01563C  

   Li, Zi-Qi; He, Wen-Ji; Ni, Hui-Qi; Engle, Keary M. (May 2022, Chemical Science)

   We report a regioselective, nickel-catalyzed syn-1,2-carbosulfenylation of non-conjugated alkenyl carbonyl compounds with alkyl/arylzinc nucleophiles and tailored N–S electrophiles. This method allows the simultaneous installation of a variety of C(sp3) and S(Ar) (or Se(Ar)) groups on to unactivated alkenes, which complements previously developed 1,2-carbosulfenylation methodology in which only C(sp2) nucleophiles are compatible. A bidentate directing auxiliary controls regioselectivity, promotes high syn-stereoselectivity with a variety of E- and Z- internal alkenes, and enables the use of a variety of electrophilic sulfenyl (and seleno) electrophiles. Among compatible electrophiles, those with N-alkyl-benzamide leaving groups were found to be especially effective, as determined through comprehensive structure–reactivity mapping. 

   more » « less
3. Spirocyclic Products via Carbene Intermediates from Thermolysis of 1,2-Dialkynylpyrrole and 1,2-Diethynylimidazole

   https://doi.org/10.1055/s-0041-1737937  

   Jewett, Ashley L.; Bondoc, Joshua A.; Gilbreath, Bradford L.; Reinus, Brandon J.; Kerwin, Sean M. (April 2022, Synlett)

   Abstract The thermal rearrangements of 1,2-dialkynylimidazoles have been shown to lead to trapping products of cyclopenta[b]pyrazine carbene intermediates. Here we show that a similar rearrangement also occurs in the case of 1,2-diethynyl-1H-pyrrole, and that trapping the intermediate cyclopenta[b]pyridine carbene with solvent THF affords an ylide that undergoes a Stevens rearrangement to a spirocyclic product. An analogous rearrangement and trapping is observed for thermolysis of 1,2-dialkynylimidazoles in THF or 1,4-dioxane. 

   more » « less
4. Three-Component Ni-Catalyzed Silylacylation of Alkenes

   https://doi.org/10.1021/acscatal.0c05449  

   Ni, Dongshun; Brown, M. Kevin (January 2021, ACS Catalysis)

   null (Ed.)

   A Ni-catalyzed silylacylation of alkenes is presented. The reaction combines alkenes, ClZnSiR3, and acid chlorides to provide rapid access to β-silyl ketones. Importantly, the method involves a [Ni]-SiR3 complex as a catalytic intermediate, which is rarely described for three-component alkene functionalization. Finally, the synthetic utility of the products is demonstrated, and the mechanistic details are described. 

   more » « less
5. Accelerated reduction and solubilization of elemental sulfur by 1,2-aminothiols

   https://doi.org/10.1039/D1CC05242J  

   Stoffel, Jonathan T.; Riordan, Kimberly T.; Tsui, Emily Y. (November 2021, Chemical Communications)

   Nucleophilic 1,2-aminothiol compounds readily reduce typically-insoluble elemental sulfur to polysulfides in both water and nonpolar organic solvents. The resulting anionic polysulfide species are stabilized through hydrogen-bonding interactions with the proximal amine moieties. These interactions can facilitate sulfur transfer to alkenes. 

   more » « less