Palladium-catalyzed decarboxylative (4 + 3) cycloadditions of bicyclobutanes with 2-alkylidenetrimethylene carbonates for the synthesis of 2-oxabicyclo[4.1.1]octanes

• Published in: Chemical science (Cambridge) Vol. 15; no. 34; pp. 13942 - 13948
• Main Authors: Gao, Xin-Yu, Tang, Lei, Zhang, Xu, Feng, Jian-Jun
• Format: Journal Article
• Language: English
• Published: CAMBRIDGE Royal Soc Chemistry 28.08.2024; Royal Society of Chemistry; The Royal Society of Chemistry
• Subjects: Alkanes; Carbonates; Chemical reactions; Chemical synthesis; Chemistry; Chemistry, Multidisciplinary; Cycloaddition; Dipoles; Octanes; Palladium; Physical Sciences; Science & Technology; Substrates; CHEMISTRY; 2-PI+2-SIGMA CYCLOADDITIONS; COMPLEXITY
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/d4sc02998d

While cycloaddition reactions of bicyclobutanes (BCBs) have emerged as a potent method for synthesizing (hetero-)bicyclo[ n .1.1]alkanes (usually n ≤ 3), their utilization in the synthesis of bicyclo[4.1.1]octane derivatives (BCOs) is still underdeveloped. Here, a palladium-catalyzed formal (4 + 3) reaction of BCBs with 1,4-O/C dipole precursors for the synthesis of oxa-BCOs is described. Unlike previous catalytic polar (3 + X) cycloadditions of BCBs, which are typically achieved through the activation of BCB substrates, the current reaction represents a novel strategy for realizing the cycloaddition of BCBs through the activation of the "X" cycloaddition partner. Moreover, the obtained functionalized oxa-BCOs products can be readily modified through various synthetic transformations. A novel palladium-catalyzed strategy was employed to achieve higher-order (4 + 3) cycloadditions of bicyclobutanes with various 2-alkylidenetrimethylene carbonates to synthesize 2-oxabicyclo[4.1.1]octanes.