First example of samarium diiodide-promoted sequential cyclization and ring-expansion reactions of α-bromomethyl cyclic β-keto esters to homologated γ-keto esters
摘要:
SmI2 reductions of some aromatic as well as aliphatic alpha-bromomethyl cyclic beta-keto esters produced one-carbon homologated gamma-keto esters in modest to good yields. (C) 1998 published by Elsevier Science Ltd. All rights reserved.
Tris(trimethylsilyl)silane (TTMSS) promoted free radical reaction in benzotrifluoride (BTF) was investigated. Compared to same reaction using environmentally less desirable tri-n-butyltin hydride (TBTH) in benzene, less quantity of BTF than that of benzene can be used because of slower hydrogen atom transfer from TTMSS than that from TBTH toward primary alkyl radicals. Also, electron-transfer reactions
palladium-catalyzed Dowd–Beckwith ringexpansion/C–C bond formation cascade is described. A range of six to nine-membered β-alkenylated cyclic ketones possessing a quaternary carbon center were accessed under mild conditions. Besides styrenes, the electron-rich alkenes such as silyl enol ethers and enamides were also compatible, providing the desired β-alkylated cyclic ketones in moderate to good yields.
First example of samarium diiodide-promoted sequential cyclization and ring-expansion reactions of α-bromomethyl cyclic β-keto esters to homologated γ-keto esters
SmI2 reductions of some aromatic as well as aliphatic alpha-bromomethyl cyclic beta-keto esters produced one-carbon homologated gamma-keto esters in modest to good yields. (C) 1998 published by Elsevier Science Ltd. All rights reserved.
Ring expansion of benzocyclic ketones via transient alkoxyl radicals: The side chain incorporation approach