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Efficient Synthesis of 5‐Chalcogenyl‐1,3‐oxazin‐2‐ones by Chalcogen‐Mediated Yne–Carbamate Cyclisation: An Experimental and Theoretical Study
Author(s) -
Monleón Alicia,
Blay Gonzalo,
Domingo Luis R.,
Muñoz M. Carmen,
Pedro José R.
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.201403169
Subject(s) - chemistry , chalcogen , regioselectivity , moiety , electrophile , ring (chemistry) , reagent , carbamate , organic chemistry , medicinal chemistry , combinatorial chemistry , stereochemistry , catalysis
A very efficient synthesis of 5‐chalcogenyl‐1,3‐oxazin‐2‐ones has been accomplished by the chalcogen‐mediated yne–carbamate cyclisation of chiral, non‐racemic N ‐Cbz‐protected propargylic amines using PhXY (X = Se, S, Te; Y = Br or Cl) as electrophile sources. The reactions gave good‐to‐excellent yields for a wide range of substrates. In all cases the reaction was totally regioselective, occurring by a 6‐ endo ‐ dig process regardless of the nature of the reagent and of the substituents in the starting material. This methodology permits the formation of the 1,3‐oxazin‐2‐one moiety as well as the simultaneous installation of a chalcogen functionality onto the heterocyclic ring. The experimental results have been rationalised by theoretical studies at the B3LYP/6‐311G* level of theory.