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A rhodium‐catalyzed remote C(sp3)−H borylation of silyl enol ethers (SEEs, E/Z mixtures) by alkene isomerization and hydroboration is reported. The reaction exhibits mild reaction conditions and excellent functional‐group tolerance. This method is compatible with an array of SEEs, including linear and branched SEEs derived from aldehydes and ketones, and provides direct access to a broad range of structurally diverse 1,n‐borylethers in excellent regioselectivities and good yields. These compounds are precursors to various valuable chemicals, such as 1,n‐diols and aminoalcohols. [ABSTRACT FROM AUTHOR]

We herein report a new H2 activation mechanism to elucidate the N-formylation of amines with CO2 and H2, catalyzed by Ru(ii) pincer complexes in the absence of exogenous additives. Furthermore, we show that the mechanism could be applied to other types of Ru(ii) pincer complexes and computed iron analogs. [ABSTRACT FROM AUTHOR]

Density functional theory calculations have been performed to provide mechanistic insight into a series of Cp*CoIII- and Cp*RhIII-catalyzed directed C-H bond functionalizations with diazo-compound substrates. Co-based catalysis proceeds through five steps: C-H bond activation; C-C coupling via a concerted 1,2-aryl transfer; proto-demetalation; nucleophilic addition; and solvent-assisted methanol elimination. C-H bond activation is predicted to be reversible, consistent with deuterium-scrambling experiments. The higher Lewis acidity of Co compared to Rh for two otherwise identical catalysts increases the susceptibility of a coordinated carbonyl group to nucleophilic addition in the former, facilitating the formation of cyclized products not observed for Rh. Methanol elimination is predicted to be the turnover-limiting step for one substrate, and this is facilitated by solvent 2,2,2-trifluoroethanol (TFE) acting as a proton shuttle. Theory suggests that further tuning of acidity may offer opportunities for improving catalysis. We also assess the role of a pyridine group that leads to a different series of final steps in one Rh-based catalytic cycle, thereby enabling access to the otherwise suppressed cyclization product. Our study of an alternative Rh-based system having acetate ligands replaced with MeCN indicates that C-H bond activation is sensitive to those ligands and variation can affect which step is turnover-limiting. [ABSTRACT FROM AUTHOR]

Ring-opening of bicyclo[1.1.0]butanes (BCBs) is emerging as a powerful strategy for 1,3-difunctionalized cyclobutane synthesis. However, reported radical strain-release reactions are typically plagued with diastereoselectivity issues. Herein, an atom-economic protocol for the highly chemo- and diastereoselective polar strain-release ring-opening of BCBs with hydroxyarenes catalyzed by a π-acid catalyst AgBF 4 has been developed. The use of readily available starting materials, low catalyst loading, high selectivity (up to >98 : 2 d.r.), a broad substrate scope, ease of scale-up, and versatile functionalizations of the cyclobutane products make this approach very attractive for the synthesis of 1,1,3-trisubstituted cyclobutanes. Moreover, control experiments and theoretical calculations were performed to illustrate the reaction mechanism and selectivity., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Reported here is a concise total synthesis of (-)-berkelic acid in eight linear steps. This synthesis features a Catellani reaction/oxa-Michael cascade for the construction of the isochroman scaffold, a one-pot deprotection/spiroacetalization operation for the formation of the tetracyclic core structure, and a late-stage Ni-catalyzed reductive coupling for the introduction of the lateral chain. Notably, four stereocenters are established from a single existing chiral center with excellent stereocontrol during the deprotection/spiroacetalization process. Stereocontrol of the intriguing deprotection/spiroacetalization process is supported by DFT calculations., (© 2020 Wiley-VCH GmbH.)

A simple and efficient protocol to generate amidyl radicals from amine functionalities through a manganese-mediated atom-transfer reaction has been developed. This approach employs an earth-abundant and inexpensive manganese complex, Mn 2 (CO) 10 , as the catalyst and visible light as the energy input. Using this strategy, site-selective chlorination of unactivated C(sp 3 )-H bonds of aliphatic amines and intramolecular/intermolecular chloroaminations of unactivated alkenes were readily realized under mild reaction conditions, thus providing efficient access to a range of synthetically valuable alkyl chlorides, chlorinated pyrrolidines, and vicinal chloroamine derivatives. These practical reactions exhibit a broad substrate scope and tolerate a wide array of functional groups, and complex molecules including various marketed drug derivatives., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A rhodium-catalyzed remote C(sp 3 )-H borylation of silyl enol ethers (SEEs, E/Z mixtures) by alkene isomerization and hydroboration is reported. The reaction exhibits mild reaction conditions and excellent functional-group tolerance. This method is compatible with an array of SEEs, including linear and branched SEEs derived from aldehydes and ketones, and provides direct access to a broad range of structurally diverse 1,n-borylethers in excellent regioselectivities and good yields. These compounds are precursors to various valuable chemicals, such as 1,n-diols and aminoalcohols., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)