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Diastereoselective [4+1] Cycloaddition of Alkenyl Propargylic Tertiary Acetates with CO Catalyzed by [RhCl(CO) 2 ] 2
Author(s) -
Zhang Yanjin,
Zhao Gang,
Pu Lin
Publication year - 2017
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.201701369
Subject(s) - chemistry , cycloaddition , acetic anhydride , medicinal chemistry , substituent , aryl , deprotonation , nucleophile , nucleophilic substitution , organic chemistry , cyclopentenone , catalysis , ion , alkyl
Alkenyl propargylic tertiary acetates were prepared by deprotonation of the corresponding enyne followed by nucleophilic addition to ketones and then treatment with acetic anhydride. The resulting acetates were then employed in diastereoselective [4+1] cycloadditions with CO catalyzed by [RhCl(CO) 2 ] 2 to form α‐benzylidene cyclopentenone derivatives. We found the cycloadditions of the tertiary acetates to be more diastereoselective than those of the corresponding secondary acetates, as a result of increased substitution at the propargylic carbon. When an electron‐donating meta substituent, such as Me and MeO, is introduced to the aryl group at the propargylic carbon of the tertiary acetate, the diastereoselectivity improved to >8:1 ( E/Z ).