Tandem substrate scope

Scheme 9 Proposed mechanism and substrate scope for tandem alcohol oxidation/Wittig reaction/alkene hydrogenation sequence...

The group of Liu developed a copper-catalyzed radical tandem cycUzation process of isocyanides with simple alkanes or alcohols (Scheme 2.18) [98], The impressive substrate scope provides a convenient access to various alkylated phenanthridines. 

Wang et al. developed an efficient Cu(OAc)2-catalyzed oxidative tandem cyclization of benzylamine and 1,3-diketone derivatives to polysubstituted oxazoles using TBHP as oxidant (Scheme 8.69). The condition of this reaction is mild and substrate scopes are wide. Four C(sp )—H bonds are cleavaged for this transformation. The iodointermediate which was formed via C-H bond activation of 1,3-diketone under TBHP/I2 system is crucial for this reaction [115]. 

Table 3.4 Substrate scope of tandem CM/thermal Sfj2 reaction...

Using ortho-halogenated aryl aldehydes and MBH adducts as substrates, 2-carbonyl-1-indanols 136 have been synthesized in moderate to good yields via a one-pot, palladium-catalyzed tandem Heck-aldol reaction. Various MBH adducts were examined to find the scope and limitations of this process (Scheme 3.53). ... 

The carbonylative cyclization of 2-iodophenols with norbornadiene or norbornene was also carried out. In 1989, Catellani s group studied the annulation of 2-iodophenol with norbornadiene to coumarin (Scheme 3.11a). ° In this method, the elimination of cyclopentadiene via retro-Diels-Alder reaction was involved in the formation of the terminal product. Fiaud and co-workers reported the palladium-catalyzed carbonylative cyclization of 2-iodophenol with norbornene in 1997 (Scheme 3.11b). They reported that the selectivity for the production of the two regioisomers can be controlled. Catellani and co-workers studied the intramolecular cyclization of ort/zo-iodophenyl 3-butenoate to 4-methylcoumarin with a palladium catalyst. 85% of 4-methylcoumarin was produced in the presence of benzonitrile and carbon monoxide, which is compulsory (Scheme 3.12a). Silva, Costa and their co-workers reported a tandem process for the synthesis of coumarins from 2-iodophenols and enoates with the assistance of a palladium catalyst (Scheme 3.12b). The general scope of this Heck-lactonization involves E- and Z-enoates as substrates. It was shown that this reaction is sensitive to steric hindrance around the double bound in... 

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