Hetero‐Aggregate Compounds of Aryl and Alkyl Lithium Reagents: A Structurally Intriguing Aspect of Organolithium Chemistry

Abstract

Organolithium compounds are often depicted as mononuclear species. However, such compounds are in fact aggregated species and can form hetero-aggregates containing different organic groups, including heteroatom groups. In reactions involving organolithium reagents, the "pure" homo-aggregate organolithium compound can change into a hetero-aggregate, which has a different structure and reactivity to the homo-aggregate. This fact is often overlooked. When there are chiral centers in the organolithium reagent or the substrate, diastereoselective self-assembly (the preferential formation of a particular diastereoisomeric aggregate) plays a role. The importance of these contributions in understanding the structure and reactivity patterns of organolithium reagents is the focus of this Minireview.

Organocopper Compounds: From Elusive to Isolable Species, from Early Supramolecular Chemistry with RCuI Building Blocks to Mononuclear R2–nCuII and R3–mCuIII Compounds. A Personal View

“…What not has been discussed in detail thus far is that, to gain access to these arylcopper(I) compounds in reasonably pure form, we had to develop, in parallel, methods to arrive at the corresponding, pure aryllithium compounds R N Li, as these materials represent our most commonly used starting materials. 89 It was extremely rewarding that the structural features of these R N Li compounds were as fascinating as those of the R N Cu compounds: indeed, the self-assembly properties of the R N Li compounds have many characteristics in common with those encountered for the homo-and heteroleptic R N Cu compounds but also showed distinct differences. These contrasting elements are due to the polar Li−C vs the more covalent Cu−C bonding, the differences in the M−N bond strengths, and the difference in size of the respective Cu(I) and Li cations.…”

Alkali‐Metal‐Mediated Zincation of Ferrocene: Synthesis, Structure, and Reactivity of a Lithium Tmp/Zincate Reagent

“…Future work will now be directed towards pinpointing the active base species in solution that produce such an alkali-metal-mediated zincation of organic substrates. [16,17] …”

Reactivity of acyclic (pentadienyl)iron(1+) cations: Synthetic studies directed toward the frondosins

“…In particular, the signals for H-2 and H-4 each appear as a doublet of doublets (J = ca. [7][8][9][10][11][12][13][14]; the larger couplings are consistent with a trans orientation with H-1 and H-5 respectively. The chemical shifts and coupling constants for 9a are similar to those reported for the (1-methoxycarbonyl-5-phenylpentadienyl)Fe(CO)3 + cation 9b.…”

“…However, the results reveal that the regioselectivity of this reaction may depend on such subtle factors as the aggregation of these organometal species. 10 accessed by following the link in the citation at the bottom of the page. Chemistry, Vol.…”