Cycloaddition, Palladium-catalyzed

Recent Advances in Palladium-catalyzed Cycloadditions involving Trimethylenemethane and its Analogs... 

Palladium-catalyzed cycloaddition of (1) to C o has been reported to proceed in 25% yield. Interestingly, the reaction requires the C o be first treated with (PPh3)4Pd and dppe in benzene before the introduction of (1) [17]. 

Grushin VV, Alper H (1999) Activation of Otherwise Unreactive C-Cl Bonds. 3 193-225 Guitian E, Perez D, Pena D (2005) Palladium-Catalyzed Cycloaddition Reactions of Arynes. 14 109-146... 

Oxazolines can be obtained by the Lewis acid catalyzed epoxide ring opening of glycidic esters or amides (e.g., 118) with acetonitrile . Oxazolidines are available from the palladium-catalyzed cycloaddition of vinyl epoxides with imines <00H885> or the samarium-promoted reaction of ketimines (e.g., 120) with unfunctionalized... 

The classical Diels-Alder cycloaddition reaction is seldom used for the construction of the aromatic ring in arylstannanes, but a promising palladium-catalyzed cycloaddition reaction of two similar or different enynes (Equation (50)) has recently been published.175... 

After the failure of the direct synthesis of the completely unsaturated heterocycle 34, an attempt was made to synthesize the partially saturated cyclopenta[t]-l, 2-diazcpine, which then could be dehydrogenated to the 5,6-diazaazulene 34. However, this approach by starting with a 1,2-diazepine ring 36 (made successfully by following published method) and its [3+2] palladium-catalyzed cycloaddition with allyl chlorosilane 35 to the bicyclic diazepine 37 failed (Scheme 8). 

While simple unactivated cyclopropanes have yet to be used for [3 + 2] cycloaddition, Tsuji and coworkers have developed a palladium-catalyzed cycloaddition reaction using electron-deficient vinylcy-clopropanes. Thus, vinylcyclopropane (43) undergoes smooth cyclization with methyl acrylate in the presence of a palladium catalyst to give vinylcyclopentane (44) as a mixture of diasteroisomers (equation 35). The cycloaddition probably proceeds through the zwitterionic ( ir-allyl)palladium intermediate (45) and its stepwise reaction with the acrylate (equation 36). Enones such as cyclopentenone and methyl vinyl ketone will also react. Reaction of the same vinylcyclopropane with phenyl isocyanate produces vi-nyllactam (46) (equation 37).Some cycloaddition reactions with (cyclopropyl)Fp complexes have also been reported. However, the substrates are limited to SO2 and TCNE and the yields have not been disclosed (equation 38). ... 

Synthesis of 1,3-oxazolidines 285 has been described by a palladium-catalyzed cycloaddition of vinylic oxiranes 284 with Af-tosyl imines 283 (Scheme 81) <2000H(52)885>. This reaction proceeded with high yields and good regioisomeric selectivity and the palladium catalyst of choice was a 1 2 Pd(dba)2 DPPE complex. 

The palladium-catalyzed cycloaddition of the activated olefin 621a with ally lie carbonates having a hydroxy group at the terminus of the carbon chain (625) gave the corresponding cyclic ethers 626 (Scheme 191).269... 

Palladium-Catalyzed Cycloaddition of Benzyne with Allyl Derivatives.141... 

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