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Regioselective Synthesis of Angular Isocoumarinselenazoles: A Benzoselenazole‐directed, Site‐specific, Ruthenium‐catalyzed C( sp 2 )‐H Activation
Author(s) -
Dhole Sandip,
Liao JenYu,
Kumar Sunil,
Salunke Deepak B.,
Sun ChungMing
Publication year - 2018
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201701256
Subject(s) - regioselectivity , chemistry , ruthenium , alkyne , alkylation , annulation , structural isomer , catalysis , stereochemistry , ring (chemistry) , selectivity , medicinal chemistry , organic chemistry
The synthesis of new, angular isocoumarinselenazoles is described, which involves the construction of 2‐amino benzoselenazoles and their regioselective C2 N ‐alkylation and alkyne insertion. An expeditious and metal‐free synthesis of 2‐aminobenzoselenazoles by the reaction of methyl 3‐amino‐4‐fluorobenzoate and isoselenocyanates was achieved. Further N ‐alkylation of the 2‐aminobenzoselenazoles resulted the formation of two regioisomers with different reactivities towards the alkyne insertion. The regioselective construction of the α‐pyrone ring on the benzo[1,3‐ d ]selenazole skeleton was achieved via a ruthenium (II)‐catalyzed oxidative annulation. It is clear that the selenazole nitrogen plays an important role in the observed selectivity.