Muriel Billamboz

Micellar Catalysis Using a Photochromic Surfactant: Application to the Pd-Catalyzed Tsuji–Trost Reaction in Water

The first example of a Pd-catalyzed Tsuji-Trost reaction, applied in a photochromic micellar media under conventional heating and microwave irradiation, is reported. The surfactant activity and recycling ability were investigated and compared with those of a few commercially available surfactants. The synthetic photochromic surfactant proved to be efficient, recyclable, and versatile for Pd-catalyzed coupling reactions.

Azobenzenes and catalysis

Azobenzene is the most extensively used class of chromophore in a large variety of applications. Recently, the use of azobenzene derivatives was developed in catalysis especially as a promoter. This paper aims to provide a global overview of the main access to the diazo compounds from 2010 as well as their use as a reactant or a promoter in organometallic catalysis.

Self-assembly, photoresponsive behavior and transport potential of azobenzene grafted dendronized polymeric amphiphiles

Photoresponsive polymeric amphiphiles were developed by first synthesizing the polyester chain via Novozym 435 catalyzed step growth, condensation polymerization of poly[ethylene glycol bis(carboxymethyl) ether]diethylester and 2-azidopropan-1,3-diol followed by grafting with 4′-butyl-4-propargyloxy(azobenzene) and [G2.0] polyglycerol dendron by using a ‘Click chemistry’ approach. The resulting polymers were observed to form supramolecular micellar aggregates in aqueous solution. The critical aggregation concentration (CAC) was determined via fluorescence measurements and using ‘Nile red’ as a probe. The nano-structures formed in the aqueous solution were characterized by dynamic light scattering (DLS) and cryo-TEM measurements. The encapsulation potential of polymeric amphiphiles for Nile red and curcumin as well as their release via trans–cis photoisomerization of the embedded azobenzene moiety was studied, by absorbance and fluorescence spectroscopy techniques. The developed polymeric micellar systems behave as efficient photoresponsive smart nanocarriers.

Selective Pinacol Coupling on Regeneratable Supported Acids in Sole Water

Efficient pinacol coupling was developed in sole water, using a reusable heterogeneous supported acid source and zinc as cheap available metal source. This medium can be easily regenerated up to 10-fold without loss of activity. Moreover, supported acids enhance the selectivity of the pinacol coupling reaction compared with homogeneous acids.

Simple and expeditious pinacol coupling of non usual α,β-unsaturated carbonyl compounds in water

Using zinc (0) in a 5% v AcOH aqueous solution allowed the efficient pinacol coupling of aliphatic or aromatic unusual, α,β-unsaturated carbonyl compounds such as citral A in good to excellent yields (56–99%). It can also be successfully applied to acetophenone.

First Pinacol Coupling in Emulsified Water: Key Role of Surfactant and Impact of Alternative Activation Technologies

For the first time, the influence of surfactants on the radical pinacol coupling reaction is investigated. The rate and selectivity of this reductive C-C coupling are compared under three different activation technologies: thermal activation, microwave irradiation, and sonication. The use of IgepalCO520, a neutral surfactant, led to the successful conversion of aromatic or α,β-unsaturated aliphatic carbonyl compounds in moderate to excellent yield (55-90 %). An insight on the potential mechanism involved in the reaction is also proposed, based on microscopic observations and particle size measurement.

Conjugated Dienyl Derivatives by Green Bisallylic Substitution: Synthetic and Mechanistic Insight

The first palladium‐catalyzed bisallylic substitution on biobased bisallylic derivatives was explored. The developed method, performed under green conditions with microwave irradiation, led to valuable conjugated dienes. The mechanism was studied by ESI‐MS and NMR spectroscopy, which highlighted the involvement of bis‐π‐allylpalladium complexes in the catalytic cycle.