Investigating Bond-Breaking in Unstrained Rings with Quantum Chemistry

Although synthetic chemists typically regard carbon-carbon single bonds as inert, they have used metal catalysts to spring open C–C bonds in strained rings, such as cyclopropanes and cyclobutanes. Performing a similar transformation with less strained but more common five- and six-membered rings, however, has proven more difficult.

Now, synthetic and theoretical chemists report a way of opening up C–C bonds in aryl substituted cyclopentanones to produce α-tetralones—a common structural motif and versatile building block in organic synthesis. The reaction makes use of a rhodium pre-catalyst, an N-heterocyclic carbene ligand, and an amino-pyridine co-catalyst. The chemists also used this strategy to turn aryl substituted cyclohexanones into α-indanones.

The reaction was developed by University of Chicago’s Guangbin Dong and Ying Xia, and at Pitt, Peng Liu and his post doc Gang Lu studied the mechanism from a quantum chemical point of view with DFT (Density Functional Theory) calculations. The results are published in the online issue of Nature.

The main research thrusts in Peng Liu's group all pertain to approaching organic reactions from a computational standpoint; the group performs quantum mechanical calculations to explore reaction mechanisms, uses quantitative energy decomposition methods to dissect the key interactions in transition states and provide chemically meaningful interpretations, and aims at predicting new catalysts for organic and organometallic reactions.

They collaborate with experimental groups such as in this study to solve problems in organic chemistry using computational methods and programs to help address the grand challenges in synthetic chemistry. 

Read the original article here.