1-(N,N-Diisopropylcarbamoyloxy)-1-tosyl-1-alkenes-a2d1 Synthons via Tandem Umpolung

1-(N,N-Diisopropylcarbamoyloxy)-1-tosyl-alkenes have been developed as an a(2)d(1) synthon via tandem umpolung. Upon addition of Grignard reagents and further quench by carbonyl compounds, this synthon produces alpha,alpha'-branched-alpha'-oxygenated ketones. Strategically, this widely applicable method installs respectively a carbanion unit and a carbonyl unit formally onto the alpha-carbon and the carbonyl center of an aldehyde in one-pot.