Practical and Convenient Synthesis of 1,6-Di- or 1,2,5,6-Tetra-arylhexa-1,3,5-trienes by the Dimerization of Pd(0)-Complexed Alkenylcarbenes Generated from π-Allylpalladium Intermediates
摘要:
Pd(0)-complexed 3-aryl or 2,3-diaryl propenylcarbenes generated from alpha-silyl-, alpha-germyl-, or alpha-boryl-alpha-allylpalladium intermediates undergo self-dimerization to provide 1,6-di or 1,2,5,6-tetraarylhexa-1,3,5-trienes in good to high yields. This method allows the use of a pi-allylpalladium intermediate for a carbenoid precursor. Furthermore, the obtained 1,2,5,6-tetraarylhexa-1,3,5-trienes exhibit aggregation-induced emission enhancement property.
The palladium‐catalyzed cyclopropanation of strained alkenes with 3‐trimethylsilyl‐ or 3‐pinacolatoboryl‐1‐arylallyl acetate derivatives is described. This reaction gives cyclopropanation products in good to high yields with a single diastereomer, and the key step is likely to involve the formation of a palladacyclobutene complex from the α‐trimethylsilyl‐ or α‐pinacolatoboryl‐σ‐allylpalladium complex