Yu is an organic synthetic chemist who develops of new methods for functionalizing carbon-hydrogen (C–H) bonds, or C–H activation. A longstanding goal in organic synthesis, C–H activation would allow for inert, unreactive C–H bonds to be replaced with bonds to functional groups that can alter a molecule's reactivity and properties. One strategy to achieve selective C–H activation under mild conditions is to use metal-based catalysts that are guided to the targeted C–H bond by nearby directing functional groups. These directing groups often must be removed once the new functional group has been appended to the molecule. This style of C–H activation methodology could greatly simplify the synthesis of pharmaceutical drug molecules, agrochemicals, and natural products.
Yu has contributed metal palladium-catalyzed C-H bond activation promoted by "weak coordination," that is by directing group effects. Other areas of interest are the development of remote C-H bond activation, for example at the meta-position to a directing group. Since many drugs and natural products are chiral, Yu has also developed important asymmetric C-H bond activation reactions, including those templated by modified amino acids that can act as transient, chiral directing groups.