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Palladium on Carbon‐Catalyzed Benzylic Methoxylation for Synthesis of Mixed Acetals and Orthoesters
Author(s) -
Yasukawa Naoki,
Kanie Takafumi,
Kuwata Marina,
Monguchi Yasunari,
Sajiki Hironao,
Sawama Yoshinari
Publication year - 2017
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.201702278
Subject(s) - chemistry , catalysis , palladium , combinatorial chemistry , organic chemistry
The palladium on carbon (Pd/C)‐catalyzed direct methoxylation of the benzylic positions of linear benzyl and cyclic ether substrates proceeded in the presence of i ‐Pr 2 NEt under an oxygen atmosphere to give the corresponding mixed acetals. Cyclic acetal derivatives could also be converted into orthoesters. The present direct methoxylation via a carbon‐hydrogen (C−H) functionalization can be accomplished using the easily‐removed Pd/C and molecular oxygen as a green oxidant. The obtained mixed acetals were transformed into the corresponding ether products by chemoselective substitution of the methoxy group using a silyltriflate, 2,4,6‐collidine, and a nucleophile. The orthoester derivative could also be transformed into the cyclic ketal under similar reaction conditions.