Duc N. Tran

Iterative reactions of transient boronic acids enable sequential C–C bond formation

The ability to form multiple carbon-carbon bonds in a controlled sequence and thus rapidly build molecular complexity in an iterative fashion is an important goal in modern chemical synthesis. In recent times, transition-metal-catalysed coupling reactions have dominated in the development of C-C bond forming processes. A desire to reduce the reliance on precious metals and a need to obtain products with very low levels of metal impurities has brought a renewed focus on metal-free coupling processes. Here, we report the in situ preparation of reactive allylic and benzylic boronic acids, obtained by reacting flow-generated diazo compounds with boronic acids, and their application in controlled iterative C-C bond forming reactions is described. Thus far we have shown the formation of up to three C-C bonds in a sequence including the final trapping of a reactive boronic acid species with an aldehyde to generate a range of new chemical structures.

A Versatile Room‐Temperature Route to Di‐ and Trisubstituted Allenes Using Flow‐Generated Diazo Compounds

A copper-catalyzed coupling reaction between flow-generated unstabilized diazo compounds and terminal alkynes provides di- and trisubstituted allenes. This extremely mild and rapid transformation is highly tolerant of several functional groups.

Visible Light Activation of Boronic Esters Enables Efficient Photoredox C(sp2)–C(sp3) Cross-Couplings in Flow

Abstract We report herein a new method for the photoredox activation of boronic esters. Using these reagents, an efficient and high‐throughput continuous flow process was developed to perform a dual iridium‐ and nickel‐catalyzed C(sp2)–C(sp3) coupling by circumventing solubility issues associated with potassium trifluoroborate salts. Formation of an adduct with a pyridine‐derived Lewis base was found to be essential for the photoredox activation of the boronic esters. Based on these results we were able to develop a further simplified visible light mediated C(sp2)–C(sp3) coupling method using boronic esters and cyano heteroarenes under flow conditions.

Rapid Asymmetric Synthesis of Disubstituted Allenes by Coupling of Flow-Generated Diazo Compounds and Propargylated Amines

Abstract We report herein the asymmetric coupling of flow‐generated unstabilized diazo compounds and propargylated amine derivatives, using a new pyridinebis(imidazoline) ligand, a copper catalyst and base. The reaction proceeds rapidly, generating chiral allenes in 10–20 minutes with high enantioselectivity (89–98 % de/ee), moderate yields and a wide functional group tolerance.

Research data supporting "A multicomponent approach for the preparation of homoallylic alcohols"

This data contains a .zip file of the NMR spectra for the compounds (in .mnova format, to be opened in MestReNova) described in the Supporting Information. It also contains a .pdf copy of the Supporting Information, which contains the experimental details and full characterisation data (NMR, IR, HRMS) of all compounds produced in this publication.

Research data supporting “Rapid asymmetric disubstituted allene synthesis via coupling of flow-generated diazo compounds and propargylated amines”

This data contains a .zip file of the NMR spectra for the compounds (in .mnova format, to be opened in MestReNova) described in the Supporting Information. It also contains a .pdf copy of the Supporting Information, which contains the experimental details and full characterisation data (NMR, IR, HRMS) of all compounds produced in this publication.

Research data supporting "Visible Light Activation of Boronic Esters Enables Efficient Photoredox C(sp2)–C(sp3) Cross-Couplings in Flow"

This data consists of raw NMR spectra used to characterise all compounds described in the above mentioned manuscript