The effect of coordination on the reaction of N-tosyl imines with diethylzinc

The first enzyme-promoted addition of nitromethane to imines (aza-Henry reaction)

Enzyme catalytic promiscuity is the ability of a single enzyme active site to catalyze several chemical transformations, among them those which are different from natural. We have attempted to use this feature of enzymes in the nucleophilic addition of nitromethane to aldimines (the aza-Henry reaction) whose chemically catalyzed version leads to synthetically useful β-nitroamines. We succeded in obtaining for the first time the desired products in the yields up to 81%. The most efficient proved lipase TL (from Pseudomonas stutzeri) and oxynitrilase from Arabidopsis thaliana. However, all the reactions investigated were non-stereoselective.

Visible-Light, Iodine-Promoted Formation of N-Sulfonyl Imines and N-Alkylsulfonamides from Aldehydes and Hypervalent Iodine Reagents

Alternative synthetic methodology for the direct installation of sulfonamide functionality is a highly desirable goal within the domain of drug discovery and development. The formation of synthetically valuable N-sulfonyl imines from a range of aldehydes, sulfonamides, and PhI(OAc)₂ under practical and mild reaction conditions has been developed. According to mechanistic studies described within, the reaction proceeds through an initial step involving a radical initiator (generated either by visible-light or heat) to activate the reacting substrates. The reaction provides a synthetically useful and operationally simple, relatively mild alternative to the traditional formation of N-sulfonyl imines that utilizes stable, widely available reagents.

Sucrose and KF quenching system for solution phase parallel synthesis

The KF, sucrose (table sugar) exploited as quenching system in solution phase parallel synthesis. Excess of electrophiles were covalently trapped with hydroxyl functionality of sucrose and due to polar nature of sucrose derivative was solubilize in water. Potassium fluoride used to convert various excess electrophilic reagents such as acid chlorides, sulfonyl chlorides, isocyanates to corresponding fluorides, which are less susceptible for hydrolysis and subsequently sucrose traps these fluorides and dissolves them in water thus removing them from reaction mixture. Various excess electrophilic reagents such as acid chlorides, sulfonyl chlorides, and isocyanates were quenched successfully to give pure products in excellent yields.

Supported p-toluenesulfonic acid as a highly robust and eco-friendly isocyanide scavenger

We document here the use of polymer-supported p-toluenesulfonic acid as a highly effective, robust, economical and eco-friendly isocyanide scavenger. The herein described strategy circumvent the intense and repulsive odor of volatile isocyanides, enabling simplified and odorless workup and purifications. The usefulness of the new scavengers has been validated in a set of diverse isocyanide-based organic transformations and this approach is also amenable to parallel synthesis techniques.

Dimethylzinc-Mediated Alkynylation of Imines

The treatment of various aromatic and aliphatic aldimines with a mixture of a terminal alkyne and a commercially available dimethylzinc solution in toluene yields the corresponding protected propargylic amines in moderate to excellent yields. The reaction proceeds in the absence of any activator. These observations led to the development of a three-component synthesis of propargylic amines in which the product was obtained upon mixing an aldehyde with ortho-methoxyaniline and phenylacetylene in the presence of dimethylzinc, through in situ formation of the corresponding imine.

Asymmetric aza-Henry reaction ofN-tosyl imine

An efficient stereoselective aza-Henry reaction of N-tosyl imine, catalyzed by the coordination of diethylzinc with a chiral semi-aza-crown ligand, with moderate to high ee (up to 83%) is reported.