Refernces
10.1016/j.tetlet.2008.06.123
The study focuses on the synthesis of substituted 2-azabicyclo[3.2.1]octadienes, which are significant in the creation of natural products and biologically active compounds, through the ring expansion of substituted norbornadienes using toluenesulfonyl azide. The researchers explored the regioselectivity of the cycloaddition/rearrangement process with various mono- and disubstituted norbornadienes, finding that both types could be converted into the bicyclooctadiene ring system with high regiocontrol and in moderate to excellent yields. The study also investigated the impact of different substituent groups on the reaction's outcome, noting that electron-withdrawing groups resulted in little to no product, while hydroxymethyl derivatives provided a moderate yield of a single regioisomer. The synthesized 2-azabicyclo[3.2.1]octadienes can be further modified to yield highly substituted derivatives of the 2-azabicyclo[3.2.1]octane ring system, which is prevalent in natural products and pharmacologically active molecules, thus providing a valuable route for the synthesis of these complex structures.
10.1016/S0040-4039(01)80858-3
The research investigates the reaction of t-butoxy radicals with norbornadiene using the scavenger 1,1,3,3-tetramethylisoindolin-2-yloxyl (1). The purpose of this study was to elucidate the regioselectivity and stereoselectivity of the reactions of oxy radicals with olefins, which are crucial for understanding the initiation of free radical polymerization. The researchers found that the majority of the reactions involved addition reactions leading to a range of adducts, with a significant portion resulting from radical rearrangements. Notably, they observed a 1,3-H shift, which is unusual and not typically expected under the given conditions. The chemicals used in the process included di-t-butyl peroxalate (3) for generating t-butoxy radicals, norbornadiene (2) as the substrate, and 1,1,3,3-tetramethylisoindolin-2-yloxyl (1) as the radical trap. The conclusions of the study highlighted the importance of radical rearrangements in the overall reaction and the unusual feature of a 1,3-H shift, contributing to the understanding of complex radical reactions in polymerization processes.
10.1016/0022-328X(88)87050-5
The research investigates methods to enhance the efficiency and yield of the Khand reaction, a process used to synthesize cyclopentenones from alkynehexacarbonyldicobalt complexes and alkenes. The study explores the impact of ultrasonic irradiation and the addition of phosphine oxides on the reaction. Key chemicals used include various alkynehexacarbonyldicobalt complexes, alkenes such as 2,5-dihydrofuran and norbornadiene, and tributylphosphine oxide. The research found that ultrasonic irradiation allows the reaction to proceed more rapidly at lower temperatures, though it does not significantly affect yields. In contrast, the addition of tributylphosphine oxide to the reaction mixture often significantly increases yields, with enhancements of up to 50% observed in some cases. The study concludes that while ultrasonic irradiation can accelerate the reaction, the use of tributylphosphine oxide is a more effective method for improving the overall yield of the Khand reaction.
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