Chemoselective Addition of Lithium Phosphides to Aldehydes and Epoxides in Deep Eutectic Solvents

Within the arsenal of organic synthesis, the chemistry of compounds of s-block elements (typically organolithium and Grignard reagents) has become one of the most useful tools to forge new C–C. Although a variety of synthetic methods has been developed so far to create C–N, C–O and C–S bonds, the number of protocols for the construction of new C–P connections is much more limited. Pioneering, independent studies from Hevia, García-Alvarez, and our own group have shown that the rate of alkylation/arylation of unsaturated functional groups (e.g., carbonyl compounds, imines, double bonds) by highly polar organometallic compounds successfully competes with protonation, when using environmentally responsible protic solvents like water and the so-called Deep Eutectic Solvents (DESs). In this communication, we wish to report that DESs can be used as environmentally friendly reaction media to promote a fast (within 3 s reaction time) and chemoselective addition of in-situ generated highly polarized lithium phosphides (LiPR2) to both aldehydes and epoxides, working at room temperature (RT) and under aerobic conditions, thereby granting access to α- and β-hydroxy-phosphine oxides, respectively, in very good yields (up to 94%)

Fast and Chemoselective Addition of in Deep Eutectic Solvent Generated Highly Polarized Lithium Phosphides (LiPR2) to Aldehydes and Epoxides at Room Temperature and Under Air

Highly polarized lithium phosphides (LiPR2) have been synthesized, for the first time, in Deep Eutectic Solvents (DESs) as sustainable reaction media, at room temperature and in the absence of protecting atmosphere, through direct deprotonation of both aliphatic and aromatic secondary phosphines (HPR2) by n-BuLi. The subsequent addition of in-situ generated LiPR2 to aldehydes or epoxides proceeds fast and chemoselectively, thereby allowing the straightforward access to the corresponding α-hydroxy- or β-hydroxy phosphine oxides, respectively, under air and at room temperature (bench conditions), which are traditionally considered as textbookprohibited conditions in the field of polar organometallic chemistry of s-block elements

A high performance all-polymer symmetric faradaic deionization cell

Faradaic deionization (FDI) is an emerging and promising electrochemical technology for stable and efficient water desalination. Battery-type energy storage materials applied in FDI have demonstrated to achieve higher salt removal capacities than carbon-based conventional capacitive deionization (CDI) systems. However, most of the reported FDI systems are based on inorganic intercalation compounds that lack cost, safety and sustainability benefits, thereby curtailing the development of a feasible FDI cell. In this work, we introduce an all-polymer rocking chair practical FDI cell, with a symmetric system composed by a redox-active naphthalene-polyimide (named as PNDIE) buckypaper organic electrodes. First, electrochemical performance of PNDIE in 0.05 M NaCl under open-air conditions is evaluated in both three-electrode half- and symmetric FDI full-cell using typical lab-scale electrode dimensions (1.6 mgPNDIE; 0.78 cm2), revealing promising specific capacity (115 mAh g−1) and excellent cycle stability for full-cell experiments (77 % capacity retention over 1000 cycles). Then, all-polymer rocking chair FDI flow cell was constructed with practical PNDIE electrodes (92.2 mgPNDIE; 9.6 cm2) that delivered large desalination capacity (155.4 mg g−1 at 0.01 A g−1) and high salt-removal rate and productivity (3.42 mg g−1 min−1 at 0.04 A g−1 and 62 L h−1 m−2, respectively). In addition, long-term stability (23 days) experiments revealed salt adsorption capacity (SAC) retention values over 95% after 100 cycles. The overall electrochemical and deionization performances of the reported technology is far superior than the state-of-the-art CDI and FDI techniques, making it a competitive choice for robust and sustainable “water-energy” electrochemical applications

Fast and Chemoselective Addition of Highly Polarized Lithium Phosphides Generated in Deep Eutectic Solvents to Aldehydes and Epoxides

Highly polarized lithium phosphides (LiPR2) have been synthesized, for the first time, in Deep Eutectic Solvents (DESs) as sustainable reaction media, at room temperature and in the absence of protecting atmosphere, through direct deprotonation of both aliphatic and aromatic secondary phosphines (HPR2) by n-BuLi. The subsequent addition of in-situ generated LiPR2 to aldehydes or epoxides proceeds fast and chemoselectively, thereby allowing the straightforward access to the corresponding α-hydroxy- or β-hydroxy phosphine oxides, respectively, under air and at room temperature (bench conditions), which are traditionally considered as textbookprohibited conditions in the field of polar organometallic chemistry of s-block elements