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A Straightforward Hetero‐Diels–Alder Approach to (2‐ ambo ,4′ R ,8′ R )‐α/β/γ/δ‐4‐Thiatocopherol
Author(s) -
Menichetti Stefano,
Amorati Riccardo,
Bartolozzi Maria Grazia,
Pedulli Gian Franco,
Salvini Antonella,
Viglianisi Caterina
Publication year - 2010
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.200901493
Subject(s) - chemistry , chemoselectivity , diels–alder reaction , stereochemistry , regioselectivity , allylic rearrangement , organic chemistry , catalysis
A simple and original inverse electron demand hetero‐Diels–Alder reaction has been successfully applied to the synthesis of (2‐ ambo ,4′ R ,8′ R )‐α/β/γ/δ‐4‐thiatocopherol. Commercially available methyl hydroquinones and (2 E ,7 R ,11 R )‐(+)‐phytol were exploited for the preparation of the ortho ‐thioquinones, acting as electron‐poor dienes, and of the proper 1,3‐diene used as dienophile, respectively. The benzoxathiine cycloadducts, with the required tocopherol‐like skeleton, were obtained with complete control of regio and chemoselectivity. The antioxidant activity of 4‐thiatocopherols was measured and rationalized in comparison with that of the corresponding natural components of Vitamin E.