In the present work, we show for
the first time that the conversion
of aldehydes to alcohols can be achieved using “unprotected”
iridium transfer hydrogenation catalysts inside living cells. The
reactions were observed in real time by confocal fluorescence microscopy
using a Bodipy fluorogenic substrate. We propose that the reduced
cofactor nicotinamide adenine dinucleotide (NADH) is a possible hydride
source inside the cell based on studies using pyruvate as a cellular
redox modulator. We expect that this biocompatible reductive chemistry
will be broadly useful to practitioners working at the interface of
chemistry and the life sciences
