1,3-dipolar cycloaddition reactions DCRs

Abstract 1,3-Dipolar cycloaddition reactions (DCR) are atom-economic processes that permit the construction of heterocycles. Their enantioselective versions allow for the creation of up to four adjacent chiral centers in a concerted fashion. In particular, well-defined half-sandwich iridium (111) catalysts have been applied to the DCR between enals or methacrylonitrile with nitrones. Excellent yield and stereoselectivities have been achieved. Support for mechanistic proposals stems from the isolation and characterization of the tme catalysts. 

Cycloaddition reactions are a fundamental class of processes in synthetic chemistry. Within this class, the 1,3-dipolar cycloaddition reaction (DCR) has found extensive use as an efficient method for the synthesis of different heterocyclic compounds. These type of reactions involve the addition of a 1,3-dipole to a multiple 7i-bond system (dipolarophile) leading to five-membered heterocycles (Scheme 1) [1]. 

Dipolar cycloaddition reactions (DCRs) are unique reactions when considering their versatility, their atom economy and the highly functionalized heterocyclic products they provide. The significant contributions by Rolf Huisgen has led to the description of a... 

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