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Diels ‐ Alder Regioselectivity Controlled by Remote Substituents. The Cycloadditions of 1‐(Dimethoxymethyl)‐2,3‐dimethylidene‐ and ‐2,3,5,6‐tetramethylidene‐7‐oxabicyclo[2.2.1]heptanes
Author(s) -
Métral JeanLue,
Lauterwein JüRgen,
Vogel Pierre
Publication year - 1986
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19860690603
Subject(s) - regioselectivity , chemistry , ketone , reagent , lewis acids and bases , methyl vinyl ketone , diels–alder reaction , catalysis , medicinal chemistry , organic chemistry
The syntheses of 2,3‐dimethylidene‐ and 2,3,5,6‐tetramethylidene‐7‐oxabicyclo[2.2.1]heptanes substituted in position C(1) are reported. The 1‐dimethoxymethyl group in derivatives 2 and 6 controls the regioselectivity of the Lewis ‐acid‐catalyzed Diels ‐ Alder additions with methyl vinyl ketone and butynone. For the EtAlCl 2 ‐catalyzed addition of methyl vinyl ketone to 6 , the regioselectivity can be reversed by a small solvent modification. The tetraene 2 is a versatile reagent for regioselective ‘tandem’ cycloadditions.