Intramolecular Acylpalladation

The scope of reaction has been further extended to allylic electrophiles. An extensive investigation of the intramolecular acylpalladation has been performed in a series of < -iodoalkenylbenzenes with both terminal and internal double bonds and 1-iodo-substituted 1,4-, 1,5-, or 1,6-dienes. ... 

The cyclization of enynes containing propargylic carbonate fragment involves allene intermediate, which takes part in intramolecular acylpalladation by endo-frig-modc to give a six-membered ring (Scheme 23). " ... 

These reactions may as well occur in the termination stages of cascade reactions, for example, involving intramolecular acylpalladation (Scheme 30) or intramolecular Heck reaction Equation (49). ... 

Coperet C, Negishi E (2002) Intramolecular Acylpalladation Intramolecular Acylpalladation Reactions with Alkenes, Alkynes, and Related Unsaturated Compounds. In Negishi E, de Meijere A (eds) Handbook of Organopalladium Chemistry for Organic Synthesis. Wiley, New York, p 2519... 

Carbonylation of 2-iodostyrene (74) afforded indanone (75) and indenone (76) via intramolecular acylpalladation of the double bond. In the presence of BU4NCI and pyridine, protonation occurred to give indanone (75). When Et3N was used, indenone (76) was obtained. Under high pressure CO (40 atm), the keto ester 77 was the main product [35]. 

As in the cases of termination by lactonization and lactamization, some specially structured alkenes, such as norbomene and related alkenes, can participate in intermolecular carbopalladation-carbonylative ketonization tandem processes. In the reactions shown in Scheme 22, the acylpalladium intermediates undergo intramolecular acylpalladation with arenes to provide ketones. ... 

Intramolecular acylpalladation-carbonylation via palladium 7t-allyl complexes O 2-Cyclopentenon-5-ylacetic acid esters... 

VI.4.1.1 Intramolecular Acylpalladation Reactions with Alkenes, Alkynes, and Related Unsaturated Compounds... 

Reactions of acylpalladium complexes involving acylpalladation with arenes or formally equivalent processes have been much less exploited compared with those involving acylpalladation with alkenes or alkynes discussed in the previous section, and to the best of our knowledge, their examples are limited to intramolecular reactions. A few reactions that may include the intramolecular acylmetallation with arenes are known in the case of a rhodium catalyst, but the products are limited to a narrow range of compounds such as indenones.t In contrast, the Pd-catalyzed carbonylation of 3-arylaUyl acetates or hahdes, most typically cinnamyl acetate, involving intramolecular acylpalladation with arenes results in the construction of 1-naphthol, which is a hiding member of cyclic aromatic ketones. The outline of the conversion is sketched in Scheme 1. In fact, this type of carbonylation-cyclization reaction (cyclocarbonylation) can be applied to the synthesis of a variety of fused aromatics, which is summarized in the following subsection. 

Pd(OAc)2 as a catalyst is indispensable to suppress the acylpalladation. Since the intramolecular acylpalladation usually predominates over ketene generation, formation of some side products is inevitable and the yield of the cyclobutanone is unsatisfactory. 

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