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Synthesis of 7‐Membered Ring Carbocycles via a Palladium‐Catalyzed Intramolecular Allylic Alkylation–Isomerization–Cope Rearrangement Cascade
Author(s) -
Tsuruda Kazuki,
Tokumoto Takahisa,
Inoue Naoya,
Nakajima Masaya,
Nemoto Tetsuhiro
Publication year - 2018
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201800230
Subject(s) - chemistry , intramolecular force , isomerization , allylic rearrangement , cyclopropanation , palladium , tsuji–trost reaction , cascade reaction , ring (chemistry) , medicinal chemistry , cope rearrangement , stereochemistry , alkylation , intramolecular reaction , catalysis , organic chemistry
We developed a novel method for synthesizing seven‐membered ring carbocycles via a palladium‐catalyzed intramolecular allylic alkylation–isomerization–Cope rearrangement cascade. Using easily available lactone derivatives as substrates, the target cascade reaction proceeded in the presence of 5 mol‐% of Pd(dba) 2 and 6 mol‐% of 1,3‐diphenylphosphinopropane (dppp) in THF, affording a series of seven‐membered ring carbocycles in 59–88 % yield (11 examples). DFT calculations suggested that, in addition to the reaction cascade including the cis ‐divinylcyclopropane Cope rearrangement, there is another possible pathway based on the palladium‐catalyzed intramolecular allylic substitution to construct the seven‐membered ring through a retro‐cyclopropanation‐mediated oxidative addition.