Carbometalation and Heterometalation of Carbon‐Carbon Multiple‐Bonds Using Group‐13 Heavy Metals: Carbogallation, Carboindation, Heterogallation, and Heteroindation

Abstract

Organogallium and ‐indium compounds are useful reagents in organic synthesis because of their moderate stability, efficient reactivity and high chemoselectivity. Carbogallation and ‐indation of a carbon‐carbon multiple bond achieves the simultaneous formation of carbon‐carbon and carbon‐metal bonds. Heterogallation and ‐indation construct carbon‐heteroatom and carbon‐metal bonds. Therefore, these reaction systems represent a significant synthetic method for organogalliums and ‐indiums. Many chemists have attempted to apply various types of unsaturated compounds such as alkynes, alkenes, and allenes to these reaction systems. This minireview provides an overview of carboindation and ‐gallation as well as heteroindation and ‐gallation.

Bis-periazulene (Cyclohepta[def]fluorene) as a Nonalternant Isomer of Pyrene: Synthesis and Characterization of Its Triaryl Derivatives

“…An intramolecular cyclization between the aldehyde and alkyne of 5 is a direct step to constructing a heptagon (Table S1). Considering the affinity to both carbonyl and alkyne moieties, 49,50 For the deprotonation of 2 + into 1, the choice of a suitable base was important. When we applied sodium hydride to the deprotonation of 2d + , 52,53 an over-reduced radical anion 1d •− , confirmed by X-ray analysis, was unexpectedly obtained (Figure S10).…”

“…An intramolecular cyclization between the aldehyde and alkyne of 5 is a direct step to constructing a heptagon (Table S1). Considering the affinity to both carbonyl and alkyne moieties, , we applied indium­(III) salt as a Lewis acid to the cyclization. Treating 5 with In­(OTf) 3 directly gave 6 as the indium­(III) center would activate the carbonyl and facilitate cyclization.…”

The road to bis‐periazulene (cyclohepta[def]fluorene): Realizing one of the long‐standing dreams in nonalternant hydrocarbons

“…As a model reaction, an intramolecular cyclization between the aldehyde and alkyne of the biphenyl derivative 91 is noticeable because it is a possible direct step to constructing a heptagon. Considering the affinity to both carbonyl and alkyne moieties, [134,135] we applied indium(III) salt as a Lewis acid to the cyclization. Although AlCl 3 and InX 3 (X = Cl, Br, I) were unsuitable for the desired cyclization, treating 91 with In(OTf) 3 in heated toluene directly gave 92, as the indium(III) center would activate the carbonyl and facilitate cyclization (Table 1).…”

Uncatalyzed Carbometallation Involving Group 13 Elements: Carboboration and Carboalumination of Alkenes and Alkynes

“…12,13 These transformations have been reviewed. 14 Uncatalyzed carboboration and carboalumination reactions represent another class of important transformations. Compared to their transition-metal-catalyzed variants, these reactions are sustainable due to the absence of expensive and toxic heavy metals.…”