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We have recently disclosed a palladium-catalyzed Trost- Oppolzer type Alder-ene reaction of 2,4-pentadienyl acetates for the synthesis of highly substituted cyclopentadienes and cyclopentenefused aromatics. The overall transformation also represents an acid-free iso-Nazarov type cyclization. Herein, we provide the hypothesis and rationale behind this work, while highlighting the seminal contributions of Trost, Oppolzer and others towards the development of the palladium- ene reaction. [ABSTRACT FROM AUTHOR]

A facileapproach for the synthesis of furopyrans and bicyclicbisacetals under mild aqueous conditions is described. This potentiallygreen, diversity oriented approach involves cascade Michael additionand cycloacetalization of pyranones and 1,3-dicarbonyls. An interestingswitch in the product class was observed depending on the type ofpyranone employed. Products of type Iand IIobtained herein are an integral part of several bioactive naturalproducts and medicinally interesting compounds. [ABSTRACT FROM AUTHOR]

A new approach to the synthesis of highly substituted cyclopentadienes, indenes, and cyclopentene-fused heteroarenes by means of the Pd-catalyzed Trost-Oppolzer-type intramolecular Alder-ene reaction of 2,4-pentadienyl acetates is described. This unprecedented transformation combines the electrophilic features of the Tsuji-Trost reaction with the nucleophilic features of the Alder-ene reaction. The overall outcome can be perceived as a hitherto unknown "acid-free" iso-Nazarov-type cyclization. The versatility of this strategy was further demonstrated by the formal synthesis of paucifloral F, a resveratrol-based natural product., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)