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Reaction of Bicyclic Zirconacyclopentenes with Aldehydes and a Potential Pathway to Condensed 5–7–6(Ar) Ring Systems
Author(s) -
Topolovčan Nikola,
Panov Illia,
Kotora Martin
Publication year - 2015
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.201500248
Subject(s) - chemistry , bicyclic molecule , intramolecular force , aryl , ring (chemistry) , reagent , medicinal chemistry , alkyl , halide , stereoselectivity , negishi coupling , stereochemistry , organic chemistry , catalysis
Bicyclic zirconacyclopentenes prepared by the reactions of 1,6‐ and 1,7‐enynes with [Cp 2 ZrBu 2 ] (Negishi reagent) reacted with a plethora of aldehydes (aryl, heteroaryl, alkyl, α,β‐unsaturated) by chemo‐ and stereoselective insertion into the sp 3 C–Zr bond to give the corresponding oxazirconacycloheptenes. Subsequent hydrolysis or halogenolysis provided the corresponding alcohols 4 (31–74 % isolated yields) or halides 10 (35–50 % isolated yields). The oxazirconacycloheptenes prepared by the insertion of 2‐iodobenzaldehyde were also subjected to intramolecular coupling in the presence of CuCl and additives, and compounds possessing the condensed 5–7–6(aryl) ring system were obtained in reasonable isolated yields (32–46 %). The same ring system was also prepared by the Pd‐catalyzed coupling of dihalo derivatives 10 (38–42 % 1 H NMR yields). Moreover, the mechanism of the unproductive side‐reaction leading to ketones during the reaction with CuCl was elucidated.