Organo-SOMO-Catalyzed Asymmetric Alkylations of Arenes

4 Organo-SOMO-Catalyzed Asymmetric Alkylations of Arenes 

Very recently, this methodology was utilized by both Nicolaou [36] and MacMillan [37] groups in the selective a-arylation of aldehydes by using not prefunctionalized benzene-like rings. The process could also be conveniently conceptualized also in terms of catalytic asymmetric FC-type alkylation reaction and, therefore, deserves particular mention. 

Nicolaou s team envisioned the possibility to apply the asymmetric SOMO catalysis in the key step of the total synthesis of calamenene. Basically, the strategy concerns the use of acyclic alde-hydic compounds 71 carrying electron-rich arene as model substrates and CAN (i.e., cerium(IV) 

SCHEME 5.20 Br0nsted acid (BA)-catalyzed alkylation of aromatic hydiocaibons. (a) Synthesis of indenes and (b) enantioselective alkylation of alkoxybenzene via electrophilic indoKmum intermediates. 

FIGURE 5.5 Single electron transfer (SET) oxidation of an in situ formed enamine to obtain electrophilic radical cations. 

---