Chiral ligands Fujiwara-Moritani reaction

By using an LX-type ligand, the catalytic asymmetric Fujiwara-Moritani reaction of benzene with cyclic olefins can afford the chiral phenyl-substituted cyclic olefins through syn p-H elimination from the opposite (y) side to the phenyl group (Scheme 32) [160]. 

In 1999, Mikami and co-workers reported the first example of asymmetric Fujiwara-Moritani reaction catalyzed by Pd" and sulfonylamino-oxazoline ligand (Scheme 5.12a). A 1 1 complex between the chiral ligand and Pd(OAc)2 could be the active catalyst in this asymmetric Fujiwara-Moritani reaction. This method provides a convenient process to synthesize aromatic C—H bond activation/olefin coupling products but with moderate enantioselectivity. 

In 1999, Mikami s group reported the first example of an intermolecular asymmetric Fujiwara-Moritani reaction of benzene with cyclic alkenes using a Pd catalyst co-ordinating to a chiral sulfonylamide-oxazoline ligand (Scheme 7.24). With PhCOs Bu as the oxidant, the coupling reaction occurred with moderate enantioselectivity (up to 49% ee), although the chemical yield was low. The reaction is considered to involve the formation of a phenyl-Pd species via electrophilic C-H substitution by Pd(ii), and Heck-type cyclization followed by re-oxidation of the resultant Pd(0) species. 

Oestreich and co-workers reported an enantioselective intramolecular Fujiwara-Moritani reaction of indole and pyrrole derivatives. Using a suitable oxidant e.g., PhCOg Bu, benzoquinone, O2), they evaluated a chiral bidentate pyridyl-oxazoline ligand (PyOx) developed by Stolz and a series of nicotine-oxazoline ligands (NicOx) with Pd(OAc)2 as a catalyst precursor (Scheme 7.25). Indoles and pyrroles underwent a 5-exo-trig cyclization, but the chemical yield and enantioselectivity were generally unsatisfactoiy. 

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