T. Bauer, C. Chapuis, A. Jeżewski
May 1, 1996
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0
Influential Citations
41
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Journal
Tetrahedron-asymmetry
Abstract
Abstract The chiral heterodienophile N -glyoxyloyl-(2 R )-bornane-10,2-sultam 2 , readily prepared from (2 R )-bornane-10,2-sultam 1 , was used in noncatalyzed atmospheric and high-pressure as well as in [Eu(fod) 3 ]-catalyzed [4+2] cycloadditions with 1-methoxybuta-1,3-diene 3 . All the [4+2] cycloadditions studied led to diastereoisomeric mixtures of 6-substituted derivatives of 2-methoxy-5,6-dihydro-2H-pyran 4–7 . The extent of asymmetric induction in these reactions was established by 1 H NMR analysis and the absolute configuration of the thermodynamically stable products 5 and 7 by X-ray analysis, and independently by chemical correlation. Stereochemical models for both noncatalyzed and [Eu(fod) 3 ]-promoted reactions are proposed. The [4+2] cycloadduct 5 was then effectively transformed into (4 R )-hydroxy-(6S)-hydroxymethyltetrahydropyrone-2 12 , a key synthon for the lactone moiety of compactin 10 and mevinolin 11 .