Intramolecular 7-<i>endo</i>-<i>dig</i>-Selective Carbosilylation of Internal Alkynes Involving Silylium-Ion Regeneration
作者:Honghua Zuo、Hendrik F. T. Klare、Martin Oestreich
DOI:10.1021/acs.joc.3c00261
日期:2023.3.17
A catalytic silylium-ion-promoted intramolecular alkyne carbosilylation reaction is reported. The ring closure is initiated by electrophilic activation of the C–C triple bond by a silylium ion, and the catalytic cycle is then maintained by the protodesilylation of a stoichiometrically added allylsilane reagent. Exclusive 7-endo-dig selectivity is seen, leading to a series of silylated benzocycloheptene
Brønsted Acid‐Catalyzed Intramolecular 7‐<i>endo</i> Hydroarylation Reaction of 1,5‐Diaryl‐1‐pentynes
作者:Kosho Makino、Shunsuke Sueki、Masahiro Anada
DOI:10.1002/adsc.202300220
日期:2023.5.12
A Brønstedacid-catalyzed, transition metal-free intramolecular 7-endo hydroarylation reaction of 1,5-diaryl-1-pentynes has been developed. The use of 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as a solvent was found to be critical for this process. Using the present methodology, we have accomplished the synthesis of KGP-18, an analogue of the anticancer natural product combretastatin A4.