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Cover Feature: A New Insight into the Stereoelectronic Control of the Pd 0 ‐Catalyzed Allylic Substitution: Application for the Synthesis of Multisubstituted Pyran‐2‐ones via an Unusual 1,3‐Transposition (Chem. Eur. J. 34/2019)
Author(s) -
Brůža Zbyněk,
Kratochvíl Jiří,
Harvey Jeremy N.,
Rulíšek Lubomír,
Nováková Lucie,
Maříková Jana,
Kuneš Jiří,
Kočovský Pavel,
Pour Milan
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201901743
Subject(s) - allylic rearrangement , dihydropyran , moiety , alkane stereochemistry , substitution (logic) , stereochemistry , chemistry , catalysis , pyran , crystallography , crystal structure , organic chemistry , computer science , programming language
A new insight into Pd‐catalyzed allylic substitution shows that it is the pyramidalization of the C−C moiety of the initially formed η 2 ‐palladacycle that plays the key role in its conversion into the pivotal η 3 ‐complex. Herein, the epoxide‐like geometry of the η 2 ‐intermediate allows a favorable antiperiplanar alignment of the Pd−C and allylic C−X bonds, so that the reaction is not limited to the substrates with the C−X bond perpendicular to the C=C plane as was previously thought. This is demonstrated by the rearrangement of the nearly planar 4‐alkylidene‐5,6‐dihydropyran‐2‐ones to 6‐substituted‐4‐methylene‐5,6‐dihydropyran‐2‐ones. More information can be found in the Full Paper by L. Rulíšek, P. Kočovský, M. Pour et al. on page 8053.