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The manuscript describes a synthetic route for the formation of 5‐(methylisoindole‐1,3‐dione) pyrimidinones by [4+2] cycloaddition reactions of functionalized 1,3‐diazabuta‐1,3‐dienes with 2‐(3‐Oxo‐allyl)‐isoindole‐1,3‐dione generated in situ from phthaloylalanine and tosyl chloride using triethylamine as a base. The functionalized 5‐(methylisoindole‐1,3‐dione) pyrimidinones were further explored in the deprotection of amines to afford a variety of 5‐methylamino pyrimidinones. The synthesis of such functionalized pyrimidinones is significant as they have a wide range of pharmacological profiles and are valuable as organic synthons. Mechanistic insights are also proposed for the given synthetic methodology. [ABSTRACT FROM AUTHOR]

[3+2+2] Cycloaddition reactions are of key importance in organic chemistry for the synthesis of seven-membered mono- and condensed carbocycles. This review article summarises the different reports on transition-metal-catalysed [3+2+2] cycloaddition reactions since 2000. Different transitionmetals, such as Ni, Rh, Pd, Co, or Ru, which have been earlier reported for higher order [3+2+2] cycloaddition reactions are summarized in this article. The [3+2+2] cycloadditions of different functionalized substrates afford cycloheptane derivatives, 6-7,5-7 condensed bicyclic carbocycles, or 5-7-5 or 6-7-5 condensed tricyclic carbocycles. These higher order cycloaddition reactions may provide an easy route for the total synthesis of natural products, or as a preferable key synthetic step leading to final structure. [ABSTRACT FROM AUTHOR]

The reactions of butadienylketene with variety of 1,4-diazabuta-1,3-dienes are studied. The reactions resulted in the formation of previously unknown functionalized cis butadienyl-4-iminomethyl-azetidin-2-ones and butenylidene-butadienyl-[2,2′-biazetidine]-4,4′- diones. Butadienyl ketene reacts in fashion with both iminic portion of 1,4- diazabuta-1,3-dienes and competitive [4+2] of 1,4-diazabuta-1,3-dienes as 4π component with butadienyl ketene as 2π component are not observed. [ABSTRACT FROM AUTHOR]

A Rh-catalyzed intramolecular [3+2+2] cycloaddition is reported. The cycloaddition affords synthetically relevant 5,7,5-fused tricyclic systems of type 2 from readily available dienyne precursors. The transformation takes place with moderate or good yields, high diastereoselectivity, and total chemoselectivity. [ABSTRACT FROM AUTHOR]

The reactions of in situ-generated butadienylketene with 1,4-diazabuta-1,3-dienes are studied. [ABSTRACT FROM AUTHOR]

The cycloaddition reactions are performed under conventional heating conditions or microwave irradiation to form cyclopentane derivatives. [ABSTRACT FROM AUTHOR]

leading to 5,7,5-fused tricyclic systems [ABSTRACT FROM AUTHOR]