We describe herein the development of the first iridium-catalyzed allylic substitution using arylzinc nucleophiles. High enantioselectivities were obtained from the reactions, which used commercially available Grignard reagents as the starting materials. This methodology was also shown to be compatible with halogen/metal exchange reactions. Its synthetic potential is demonstrated by its application towards the formal synthesis of (+)-sertraline.
Thanks to iridium catalysis, arylzinc reagents undergo regioselective allylic substitution with very high enantioselectivity, when associated with phosphoramidite ligands.
The work presented herein proposes to turn the growing environmental threat posed by coffee waste disposal into an opportunity by proposing a number of valorization routes of waste coffee grounds (WCG) through biorefining. In this process, various steps were studied: drying of WCG on small and medium scales, coffee oil extraction from small to large scale, conversion of coffee oil into biodiesel, and suggestions of designs for the recycling of de-oiled WCG into briquettes. Drying was found to be best performed using an elevated hot air tunnel rather an electric pan or a motorized stirrer. Solvent extraction of coffee oil from dried WCG on a 2000 g scale afforded a 9.2 wt% yield and a solvent recovery yield of 94 vol%. This oil was successfully converted into fatty acid methyl esters biodiesel with a 58% yield. Several original and cost-effective designs were tested, some of which being readily reproducible in most laboratory settings.
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