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Premium Cyclization Reactions of Aryl Propargyl Acetates with Tethered Epoxide Induced by Ruthenium Complex
Feng YiJhen,
Chen YiHsin,
Huang ShouLing,
Liu YiHung,
Lin YingChih
Publication year2017
Publication title
chemistry – an asian journal
Resource typeJournals
Abstract Reactions of the ruthenium complex [Ru]Cl ([Ru]=Cp(PPh 3 ) 2 Ru; Cp=η 5 ‐C 5 H 5 ) with several aryl propargyl acetates, each with an ortho ‐substituted chain of various length containing an epoxide on the aromatic ring and with or without methyl substitutents on the epoxide ring, bring about novel cyclizations. The cyclization reactions of HC≡CCH(OAc)(C 6 H 4 )CH 2 (RC 2 H 2 O) (R=H, 6 a ; R=CH 3 , 6 b , where RC 2 H 2 O is an epoxide ring) in MeOH give the vinylidene complexes  5 a – b , respectively, each with the Cβ integrated into a tetrahydro‐5 H ‐benzo[7]annulen‐6‐ol ring. A C−C bond formation takes place between the propargyl acetate and the less substituted carbon of the epoxide ring. Further cyclizations of 5 a – b induced by HBF 4 give the corresponding vinylidene complexes  8 a – b each with a new 8‐oxabicyclo‐[3.2.1]octane ring by removal of a methanol molecule in high yield. For similar aryl propargyl acetates with a shorter epoxide chain, the cyclization gives a mixture of a vinylidene complex with a tetrahydronaphthalen‐1‐ol ring and a carbene complex with a tricyclic indeno‐furan ring. For the cyclization of 18 , with a longer epoxide chain, opening of the epoxide is required to afford the vicinal bromohydrin 22 , then tandem cyclization occurs in one pot. Products are characterized by spectroscopic methods as well as by XRD analysis.
Subject(s)alkyl , aryl , catalysis , chemistry , epoxide , medicinal chemistry , organic chemistry , propargyl , ring (chemistry) , ruthenium , stereochemistry
SCImago Journal Rank1.18

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