A new and highly effective organometallic approach to 1,2-dehalogenations and related reactions

A green solvent approach to the chemistry of 1,2‐diaryl‐1,2‐disodioethanes

“…Solutions of dianions 2a , 2b , 2c in CPME and 2‐MeTHF proved stable when stored under dry Ar in a refrigerator for at least 24 h, as determined by quenching small aliquots with D 2 O followed by 1 H‐NMR analysis of crude mixtures. For the stabilities of THF solutions of these organometals, see Azzena et al . [4a,b] .…”

“…Starting materials were of the highest commercial quality and were purified by distillation or recrystallization immediately prior to use, except for compound 1c , which was synthesized according to the literature . [4b] All reactions were run under dry Ar.…”

“…Na metal (chunks) was 99% purity; Na sand in CPME was prepared in a two‐necked flask equipped with reflux condenser by magnetically stirring the freshly cut metal at a temperature above its melting point for 10–15 min, followed by cooling at room temperature without stirring. 0.2 m solutions of dianions 2a , 2b , 2c in dry 2‐MeTHF or CPME were prepared according to a procedure similar to that already described employing THF as a solvent . CPME was distilled from Na and 2‐MeTHF was distilled from Na/K alloy under N 2 immediately prior to use.…”

“…After evaporation of the solvent, the resulting mixtures were analyzed by 1 H NMR. Reaction products were characterized by comparison with literature data . [4b]…”

“…In this field, we have recently shown that 1,2‐diaryl‐1,2‐disodioethanes are an interesting class of vic ‐diorganometals endowed with multipurpose chemical properties. Indeed, they behave as nucleophiles in the stereoselective synthesis of trans ‐1,2‐diarylcyclopentanes, as tunable single‐electron transfer (SET) reducing agents successfully employed, inter alia , in the degradation of halogenated organic pollutants, [4c,d] as well as organic bases . These 1,2‐dianions are easily prepared by the reductive sodiation of the corresponding 1,2‐diarylethenes, a reaction usually performed in dry tetrahydrofuran (THF).…”