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Intramolecular Hetero‐Diels–Alder Reactions of Oxadienes: Influence of Substituents of the Tether on the Diastereoselectivity
Author(s) -
Tietze Lutz F.,
Brand Siegbert,
Brumby Thomas,
Fennen Jens
Publication year - 1990
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.199006651
Subject(s) - intramolecular force , steric effects , chemistry , methylcyclohexane , diels–alder reaction , stereochemistry , medicinal chemistry , organic chemistry , catalysis
How do substituents on the chain of 1 influence the stereosclectivity of the intramolecular hetero‐Diels‐Alder reaction? This question was followed up by exact analysis of the product composition of the reactions of 1 a and its methyl analogues 1 b – e with 2 to give 3a – e . It emerged that “steric” and “conformational” effects in the chair‐shaped transition structure must be differentiated and that the equatorial position of the methyl group is more strongly favored in the transition structures leading to 3c , d than in methylcyclohexane. R = H (a), α‐Me (b), β‐Me (c), γ‐Me (d), δ‐Me (e).