6372-40-3Relevant articles and documents
A Lewis Base Nucleofugality Parameter, NFB, and Its Application in an Analysis of MIDA-Boronate Hydrolysis Kinetics
García-Domínguez, Andrés,Gonzalez, Jorge A.,Leach, Andrew G.,Lloyd-Jones, Guy C.,Nichol, Gary S.,Taylor, Nicholas P.
supporting information, (2022/01/04)
The kinetics of quinuclidine displacement of BH3 from a wide range of Lewis base borane adducts have been measured. Parameterization of these rates has enabled the development of a nucleofugality scale (NFB), shown to quantify and predict the leaving group ability of a range of other Lewis bases. Additivity observed across a number of series R′3-nRnX (X = P, N; R′ = aryl, alkyl) has allowed the formulation of related substituent parameters (nfPB, nfAB), providing a means of calculating NFB values for a range of Lewis bases that extends far beyond those experimentally derived. The utility of the nucleofugality parameter is explored by the correlation of the substituent parameter nfPB with the hydrolyses rates of a series of alkyl and aryl MIDA boronates under neutral conditions. This has allowed the identification of MIDA boronates with heteroatoms proximal to the reacting center, showing unusual kinetic lability or stability to hydrolysis.
Direct and Scalable Electroreduction of Triphenylphosphine Oxide to Triphenylphosphine
Manabe, Shuhei,Sevov, Christo S.,Wong, Curt M.
, p. 3024 - 3031 (2020/03/10)
The direct and scalable electroreduction of triphenylphosphine oxide (TPPO)-the stoichiometric byproduct of some of the most common synthetic organic reactions-to triphenylphosphine (TPP) remains an unmet challenge that would dramatically reduce the cost and waste associated with performing desirable reactions that are mediated by TPP on a large scale. This report details an electrochemical methodology for the single-step reduction of TPPO to TPP using an aluminum anode in combination with a supporting electrolyte that continuously regenerates a Lewis acid from the products of anodic oxidation. The resulting Lewis acid activates TPPO for reduction at mild potentials and promotes P-O over P-C bond cleavage to selectively form TPP over other byproducts. Finally, this robust methodology is applied to (i) the reduction of synthetically useful classes of phosphine oxides, (ii) the one-pot recycling of TPPO generated from a Wittig reaction, and (iii) the gram-scale reduction of TPPO at high concentration (1 M) with continuous product extraction and in flow at high current density.
Decarboxylative Phosphine Synthesis: Insights into the Catalytic, Autocatalytic, and Inhibitory Roles of Additives and Intermediates
Jin, Shengfei,Haug, Graham C.,Nguyen, Vu T.,Flores-Hansen, Carsten,Arman, Hadi D.,Larionov, Oleg V.
, p. 9764 - 9774 (2019/10/14)
Phosphines are among the most widely used ligands, catalysts, and reagents. Current synthetic approaches to phosphines are dominated by nucleophilic displacement reactions with organometallic reagents. Here, we report a radical-based approach to phosphines that proceeds by a cross-electrophile coupling of chlorophosphines and redox-active esters. The reaction allows for the synthesis of a broad range of substituted phosphines that were not readily attainable with the present methods. Our experimental and DFT computational studies also clarified the catalytic, autocatalytic, and inhibitory roles of additives and intermediates, as well as the mechanistic details of the photocatalytic and zinc-mediated redox modes that can have implications for the mechanistic interpretation of other cross-electrophile coupling reactions.