Regioselective Fluoroalkylphosphorylation of Unactivated Alkenes by Radical-Mediated Alkoxyphosphine Rearrangement.

A novel distal radical rearrangement of alkoxyphosphine is developed for the first time and applied to the regioselective radical fluoroalkylphosphorylation of unactivated olefins. By employing a one-pot two-step reaction of (bis)homoallylic alcohols, organophosphine chlorides, and fluoroalkyl iodides under CFL (compact fluorescence light) irradiation, a series of fluoroalkylphosphorylated alkyl iodides and alcohols are easily synthesized by regiospecific installing a phosphonyl onto the inner carbon of terminal olefins and further iodination/hydroxylation. Mechanism studies reveal that the migration undergoes a distinctive radical cyclization/ß-scission on the lone electron pair of phosphorus, resulting in C-P bond formation and C-O bond cleavage.

Radical 1,4/5-Amino Shift Enables Access to Fluoroalkyl-Containing Primary ß(γ)-Aminoketones under Metal-Free Conditions.

A novel radical 1,4/5-amino shift from the oxygen center of alkene-tethered diphenyl ketoxime ethers to the carbon center to achieve high value-added fluoroalkyl-containing primary ß(γ)-amino-ketones is reported. Mechanism studies reveal that the migration is triggered by the alkene addition of fluoroalkyl radical derived from the electron donor-acceptor (EDA) complex of Togni's reagent II or fluoroalkyl iodides and quinuclidine, and involves a unique 5(6)-exo-trig cyclization of the carbon-centered radical onto the N-atom of ketoxime ethers followed by a cascade sequence of N-O bond cleavage and dehydrogenation. Notably, besides Togni's reagent II and fluoroalkyl iodides, this protocol is also compatible with other radical precursors to provide various functionalized primary aminoketones.

Photocatalytic Anti-Markovnikov Radical Hydro- and Aminooxygenation of Unactivated Alkenes Tuned by Ketoxime Carbonates.

A tunable photocatalytic method is reported for anti-Markovnikov hydro- and aminooxygenation of unactivated alkenes using readily accessible ketoxime carbonates as the diverse functionalization reagents. Mechanistic studies reveal that this reaction is initiated through an energy-transfer-promoted N-O bond homolysis of ketoxime carbonates leading to alkoxylcarbonyloxyl and iminyl radicals under visible-light photocatalysis, followed by the addition of alkoxylcarbonyloxyl radical to alkenes. By taking advantage of the different stability of the iminyl radicals, the generated carbon radical either abstracts a hydrogen atom from the media to form the anti-Markovnikov hydrooxygenation product, or it is trapped by the persistent iminyl radical to furnish the aminooxygenation product. Notably, this is the first example of direct hydrooxygenation of unactivated olefins with anti-Markovnikov regioselectivity involving an oxygen-centered radical.

Electrochemically Tuned Oxidative [4+2] Annulation and Dioxygenation of Olefins with Hydroxamic Acids.

This work represents the first [4+2] annulation of hydroxamic acids with olefins for the synthesis of benzo[c][1,2]oxazines scaffold via anode-selective electrochemical oxidation. This protocol features mild conditions, is oxidant free, shows high regioselectivity and stereoselectivity, broad substrate scope of both alkenes and hydroxamic acids, and is compatible with terpenes, peptides, and steroids. Significantly, the dioxygenation of olefins employing hydroxamic acid is also successfully achieved by switching the anode material under the same reaction conditions. The study not only reveals a new reactivity of hydroxamic acids and its first application in electrosynthesis but also provides a successful example of anode material-tuned product selectivity.

Cu-Catalyzed Aminoacyloxylation of Unactivated Alkenes of Unsaturated Hydrazones with Manifold Carboxylic Acids toward Ester-Functionalized Pyrazolines.

A copper-catalyzed aminoacyloxylation of unactivated alkenes of unsaturated hydrazones is achieved by using various commercially available carboxylic acids as the acyloxylating reagents and di- tert-butyl peroxide (DTBP) as the oxidant. By using this method, a sequence of structurally diversiform acyloxyl-substituted pyrazolines are efficiently synthesized. Significantly, many carboxyl-containing drugs and bioactive molecules with unprotected functional groups are compatible in this reaction.