Reactions of the Lithium Salts of the Tribenzylidenemethane Dianion, Diphenylacetone Dianion, and Related Compounds

Abstract

Potentially synthetically useful reactions of the dilithium salts of the title dianions have been investigated. Electrophilic quenching with a variety of reagents usually leads to the expected products in good yield. Quenching the diphenylacetone dianion with 1 equiv of trimethylchlorosilane, however, gives a good yield of 1,3-diphenylallene obtained by formal elimination of a trimethylsiloxy anion from an intermediate monoquenched monoanion salt. NMR studies, however, do not reveal the intermediacy of the 1,3-diphenyl-2-(trimethylsiloxy)allyl anion but rather suggest that the initial reaction site is at carbon, rather than oxygen. Oxidation of the dianions leads either to ring closure or dimerization for the tribenzylidenemethane dianion and to dimerization for the diphenylacetone dianion. The dimerization reactions are stereospecific, both with respect to the two new stereocenters produced and for the double bonds of the bis-silyl enol ether products if the dimeric bis-enolate dianion products are quenched with trimethylchlorosilane.

Synthesis of Allenes from Allylic Alcohol Derivatives Bearing a Bromine Atom Using a Palladium(0)/Diethylzinc System

“…Thus, treatment of secondary mesylate 34 with Et 2 Zn in the presence of palladium(0) yielded the corresponding internal allene 47 in 77% yield (entry 8). In analogy with the synthesis of terminal aryl allene 45 (entries 4 and 5), the acetate 36 was less reactive than the trichloroacetates 37 (compare entries 9 and 10), and the reaction of the acetate 36 was completed in 2 h at 60 °C using 5 equiv of Et 2 Zn, to afford 66% of diphenylallene 48 (entry 9). The yields of the allene 49 , were relatively low (53 and 55%; entries 12 and 13), presumably due to the volatility of 49 .…”

“…1,3-Diphenylpropa-1,2-diene (48) (Table , entry 10). The trichloroacetate 37 (26 mg, 0.058 mmol) was converted into 48 (9.1 mg, 83% yield) by treatment with Et 2 Zn−Pd(0) at room temperature for 30 min: colorless oil; 1 H NMR (300 MHz) δ 6.50 (s, 2H), 7.10−7.28 (m, 10H); 13 C NMR (75 MHz) δ 98.4 (2C), 127.0 (4C), 127.3 (2C), 128.7 (4C), 133.6 (2C), 207.8: this compound appeared to be unstable when exposed to air and light; all the data for 48 were in good agreement with the literature …”

Metal- and covalent-organic frameworks as solid-state electrolytes for metal-ion batteries

“…Such electrolytes still possess an advantageously high density of anionic hopping sites and the safety features of solid electrolytes, but obtaining higher metal cation transference numbers will likely be a challenge due to the large percentage of mobile anions. An interesting extension upon this work could involve soaking the COF in a polylithium salt [63][64][65][66][67]. This could yield the COF with equal equivalents of the polyanion immobilized within the channels, triaminoguanidinium groups within the framework itself and mobile Li + .…”

Organodilithium Intermediates as Useful Dianionic Synthons: Recent Advances

“…Reagents: i, n-BuLi (2 equiv), THF, -100 to 10ºC; ii, RNCS (1 equiv), THF, -100 to -40ºC; iii, t-BuOH (1 equiv), Et2O, -50ºC; iv, t-BuOK (1 equiv), DMSO, -50 to 20ºC; v, MeI (3 equiv), 5 to 40ºC; vi, H2O/NH4Cl, 20ºC. 1,3-dibromopropane, the benzylidenecyclohexane derivative 67 was obtained whereas oxidation with iodine provoked dimerization to yield compound 68 (Scheme 16) [37]. The equimolecular reaction of bisphosphane compounds 69 with 2,6-di(lithiobenzyl)pyridine 70 or 1,1'-dilithioferrocene 71 (both obtained by direct deprotonation with nBuLi in the presence of TMEDA) yielded the corresponding ate complexes, which after protonation led to the corresponding neutral macrocycles 72 and 73, respectively (Scheme 17) [38].…”