Despite their ubiquitous presence in synthesis, the use of polar organolithium reagents under environmentally benign conditions constitutes one of the greatest challenges in sustainable chemistry. Their high reactivity imposes the use of severely restrictive protocols (e.g., moisture‐ and oxygen‐free, toxic organic solvents, inert atmospheres, low temperatures, etc.). Making inroads towards meeting this challenge, a new air‐ and moisture‐compatible organolithium‐mediated methodology for the anionic polymerization of different olefins (e.g., styrenes and vinylpyridines) was established by pioneering the use of deep eutectic solvents (DESs) as an eco‐friendly reaction medium in this type of transformation. Fine‐tuning of the conditions (sonication of the reaction mixture at 40 °C in the absence of protecting atmosphere) along with careful choice of components of the DES [choline chloride (ChCl) and glycerol (Gly) in a 1:2 ratio] furnished the desired organic polymers (homopolymers and random copolymers) in excellent yields (up to 90 %) and low polydispersities (IPD 1.1–1.3). Remarkably, the in situ‐formed polystyril lithium intermediates exhibited a great resistance to hydrolysis in the eutectic mixture 1ChCl/2Gly (up to 1.5 h), hinting at an unexpected high stability of these otherwise highly reactive organolithium species in these unconventional reaction media. This unique stability can be exploited to create well defined block‐copolymers.

Highly polarized lithium phosphides (LiPR 2) were synthesized, for the first time, in deep eutectic solvents as sustainable reaction media, at room temperature and in the absence of protecting atmosphere, through direct deprotonation of both aliphatic and aromatic secondary phosphines (HPR 2) by n-BuLi. The subsequent addition of in-situ generated LiPR 2 to aldehydes or epoxides proceeded quickly and chemoselectively, thereby allowing the straightforward access to the corresponding αor β-hydroxy phosphine oxides, respectively, under air and at room temperature (bench conditions), which are traditionally considered as textbook-prohibited conditions in the field of polar organometallic chemistry of s-block elements.

The Cover Feature shows an unprecedented generation of highly polarized lithium phosphides (LiPR2) through direct selective deprotonation of secondary phosphines (HPR2) in the biodegradable choline chloride/glycerol eutectic mixture, at ambient temperature and under aerobic conditions, and their chemoselective addition to aldehydes or epoxides. More information can be found in the Full Paper by L. Cicco et al.