The hetero Diels−Alder reaction of nonactivated conjugated dienes 1 with arylglyoxals 2 and
glyoxylate esters 7 proceeded enantioselectively in the presence of a catalytic amount of cationic
chiral BINAP−palladium or −platinum complexes and 3 Å molecular sieves (MS3A). The addition
of MS3A effectively improved the enantioselectivity of the reaction. Excellent ee's were obtained
from the reactions of 2,3-dimethyl-1,3-butadiene (1a) and 1,3-cyclohexadiene (1d) with dienophiles
2 and 7. The square-planar structure of [Pd(S-BINAP)(PhCN)2](PF6)2 was determined by X-ray
diffraction, and a chiral induction model involving the square-planar palladium complex coordinated
with BINAP and a dienophile is proposed.
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ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
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