Monomeric lithium and sodium silylbenzyl complexes: syntheses, structures, and CO bond olefination

Abstract

Herein we report two new monomeric lithium and sodium silylbenzyl complexes, which can efficiently convert CO bond in ketones, aldehydes and amide into CC bond, i.e., conducting olefination.

Lithium, sodium and potassium enolate aggregates and monomers: syntheses and structures

“…As a part of our systematic studies of the Brønsted basicity and nucleophilicity of organo-alkali metal reagents, 20–22 9-acetylanthracene ( 1 ) was treated with lithium, sodium and potassium alkyl complexes [MCH 2 SiMe 3 ] n (M = Li, 2 -Li; 23 M = Na, 2 -Na; 24 M = K, 2 -K 25 ) in d 6 -benzene (for the NMR-scale reactions) or benzene (for the scale-up reactions) (Scheme 1). 9-Acetylanthracene was chosen as the substrate for its superior steric protection over the products, as well as the crystallinity induced by the anthracen-9-yl functional group.…”

“…Since the 2020s, our group has focused on unravelling the structural and reactivity directing roles of the two key factors in alkali metal chemistry: (1) aggregate size; 20,21 (2) metal identity. 22 Herein, we bring the effort into Li, Na and K enolate chemistry by reporting the synthesis and characterisation of a series of Li, Na, K anthracen-9-yl enolates as their aggregates and ligand-stabilised monomers.…”

New Frontiers in Organosodium Chemistry as Sustainable Alternatives to Organolithium Reagents

“…A related coordination trend has been reported by the Lu group for the structures of [(Me 6 TREN)MCH(Ph)SiMe 3 ] (M=Li or Na) in which the isolated Li containing complex shows σ bonding to the benzylic position whereas the structure of the Na containing complex shows exclusively π interactions with the aryl ring. This extreme case can be attributed to the steric demands present at the benzylic position of this particular complex [29] …”

“…This extreme case can be attributed to the steric demands present at the benzylic position of this particular complex. [29] Studying the reactivity of [NaCH 2 SiMe 3 ] ∞ from a different perspective, the Lu group have reported the reactivity of the monomer [NaCH 2 SiMe 3 (Me 6 TREN)] in the Peterson olefination reaction and disclosed divergent reactivity between the sodium alkyl and its lithium congener (Figure 9). [30,31] It was shown that [LiCH 2 SiMe 3 (Me 6 TREN)] promotes nucleophilic addition whereas [NaCH 2 SiMe 3 (Me 6 TREN)] allows for a subsequent Peterson elimination for the methylenation pathway to occur.…”

Reduction of K+ or Li+ in the Heterobimetallic Electride K+[LiN(SiMe3)2]e–

“…The accessibility of 1 allows for a comprehensive exploration of its reactivity. From the ligand perspective, our group has applied a number of multidentate neutral ligands in Group-1 metal chemistry − and has observed their cation-binding selectivity . Since 1 features a nonbinding electron and two Group-1 cations (Li + and K + ), it offers an unprecedented opportunity to probe selective reduction of Li + or K + .…”