Expanding the Toolbox of Green Chemistry for Constructing Bioactive Compounds
I. A mild and affordable method for C–S couplings under environmentally responsible micellar aqueous conditions with low nickel loadings is presented. The scope includes various heterocycles and API-related structures. Moreover, the practicability was demonstrated by a gram-scale synthesis with low residual nickel in the products detected after standard purification. Opportunities to use the aqueous medium for tandem, 1-pot applications are also demonstrated.
II. Introducing the use of nanomicelles in transaminase-catalyzed chemoenzymatic reactions enables a faster reaction rate and minimizes enzymatic inhibition. Furthermore, it allows chem- and bio-catalytic reactions to run in a single reaction vessel without switching solvents. An anti-dementia drug (S)-rivastigmine is synthesized efficiently with this new technology.
III. A green chemistry-based synthesis of lapatinib was developed. A streamlined 5- step synthesis in 3 pots was carried out in water and ethanol as the only solvents. This unprecedented method represents an opportunity for shifting from petroleum-based solvents to green solvents. Additionally, a less precious metal catalyst was involved using mild reaction conditions with less reaction time.
IV. Fluorinated compounds are one of the most important categories in pharmaceuticals. A convenient method has been developed for the synthesis of difluorocyclopropenes and difluorocyclopropanes using commercially available TMSCF2Br in the absence of solvents. Complex alkenes and alkynes can readily undergo [2+1] cycloaddition to difluorocarbene with extraordinarily low E Factors.