Allylic-Type Diindium Reagents. Reactivity toward Electrophiles and Cascade Coupling Reactions with Imines

Abstract

The allylic-type diindium reagents A and B were prepared from 3-bromo-1-iodopropene (1a) and 4-bromo-2-iodobut-2-ene (1b), respectively, and their reactions with electrophiles were investigated. The diindium reagents A and B were initially reacted with imines and the resulting vinylindium compounds were then treated with organic halides in the presence of Pd(PPh(3))(4) to give linear N-aryl and N-tosyl homoallylic amines. Diindium A is stable in a small amount of water in solvent, whereas B is easily protonated to give a crotylindium reagent. The reaction of B with benzaldehyde gives mainly the 1,3- and 1,5-diols via a spontaneous coupling with two molecules of the aldehyde, in contrast to A, which reacts with one molecule of carbonyl compounds to give the vinylindium compounds.

Imine-based [2]catenanes in water

“…The reversibility of the imine bond has been extensively used to produce complex supramolecular architectures. 9 In water, the condensation of an aldehyde and an amine is generally disfavoured 10 , 11 but can be high yielding in some cases. In nature, a mechanism central to our visual cycle involves the formation of a Schiff base between the retinal chromophore and a lysine residue positioned in the hydrophobic cavity of opsin.…”

Recent Advances in Indium-Promoted Organic Reactions

“…and immediately coupled with aryl, alkenyl or allyl halides in a tandem reaction to give 65 or 66 (Scheme 27) 107. …”

Remarkable Stability of Imino Macrocycles in Water

“…The coordinative bond between a transition‐metal ion and an imine leads to an increased stability of the imines even in water 15. But in general, imines are rather unstable and are hydrolyzed quickly if water is present 16–18. However, converse results have also been reported 19.…”