The novel intramolecular ring opening of oxabenzonorbornadienes with C1-tethered aryl halides was investigated using palladium catalysts to form fused tetracyclic frameworks. The reaction was generally found to synthesize 1,2-dihydronaphthalen-1-ol products with mild selectivity but was capable of synthesizing dehydrated naphthalene products in excellent yield and selectivity. Substituent effects on oxabenzonorbornadiene and on the iodoarene were explored along with the effects of varying tether length, where an efficient reaction was observed in nearly all cases. A total of 16 examples are reported with yields ranging from 0 to 96%.

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The development of environmentally benign, inexpensive, and earth-abundant metal catalysts is desirable from both an ecological and economic standpoint. Certainly, in the past couple decades, iron has become a key player in the development of sustainable coupling chemistry and has become an indispensable tool in organic synthesis. Over the last ten years, organic chemistry has witnessed substantial improvements in efficient synthesis because of domino reactions. These protocols are more atom-economic, produce less waste, and demand less time compared to a classical stepwise reaction. Although iron-catalyzed domino reactions require a mindset that differs from the more routine noble-metal, homogenous iron catalysis they bear the chance to enable coupling reactions that rival that of noble-metal-catalysis. This review provides an overview of iron-catalyzed domino coupling reactions of π-systems. The classifications and reactivity paradigms examined should assist readers and provide guidance for the design of novel domino reactions.

The mechanism and the origin of the regioselectivity of the rhodium/diene-catalyzed ring-opening reactions of C1-substituted oxabenzonorbornadienes with arylboronic acids has been examined using hybrid density functional theory (DFT). The overall mechanism for the reaction is considered as a four-step reaction including transmetalation, carborhodation, β-oxygen elimination, and protonolysis. The free energy profiles show that the rate-determining step is involved in the protonolysis step which differs from previous mechanistic studies on metalcatalyzed ring-opening reactions of oxabenzonorbornadienes. Additionally, it is theorized the β-oxygen elimination step is the origin of regioselectivity. DFT calculations predict the formation of the 1,2,4-trisubstituted naphthalene framework is selective over the 1,1,2-trisubstituted product, in agreement with experimental observations.

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