Organopalladium compounds cyclization reactions

Several other examples of stereoselective synthesis of polycyclic ketones, via carbonylative [2 + 2 + 1] cycloaddition of organopalladium compounds derived from norbornene and norbor-nadiene, have been reported53,54,121. These reactions are useful in the synthesis of cyclopen-tanoid compounds, such as dihydrojasmone54 The nickel-catalyzed version of this method was used in a total synthesis of methylenomycin B55 and in the stereoselective synthesis of bicy-clo[3.3.0]oct-l-en-3-one derivatives56. Thus, (E)- or (Z)-9-bromo-l-methoxy-7-nonen-2-yne (5), upon intramolecular carbonylative cyclization promoted by tetracarbonyl nickel, afford the same stereoisomer of methyl 1,2,4,5.6,6a-hexahydro-3-methoxymethyl-2-oxo-l-pentaleneac-etate (6) in 43-50% yield with a relative trans configuration of the H-l and H-6a protons. 

This review will not attempt to cover the many important reactions of functionally substituted alkynes where Pd(II) salts or organopalladium compounds (RPdX) react with the alkyne to promote cyclization onto the functionality already residing in the alkyne unit. That work has recently been reviewed by the present author in a separate book chapter, along with a large number of other... 

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