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Enantiomerically pure α′,β′-difunctionalized α,β-enones by highly diastereoselective nucleophilic alkenoylation of chiral aldehydes

✍ Scribed by Petra Tebben; Michael Reggelin; Dieter Hoppe

Book ID
104229310
Publisher
Elsevier Science
Year
1989
Tongue
French
Weight
226 KB
Volume
30
Category
Article
ISSN
0040-4039

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✦ Synopsis

The nucleophilic alkenoylation of protected chiral a-oxy and a-amino alkanals 3 by lithiated 1-(p-toluenesulfonyl)-2-alkenyl carbamates 2 proceeds with virtually complete stereoselectivity to form the syn-diastereoisomers of the title compounds 4.

Among the reagents which accomplish the nucleophilic addition of a masked a,$unsaturated acyl anion A to aldehydes or ketones (nucleophilic alkenoylation),' deprotonated O-protected cyanohydrins E are the best investigated ones." Frequently, even here, problems of chemo-and regioselectivity are encountered.3 Furthermore, to our best knowledge, reagents which add onto a-chiral aldehydes B with exclusive formation of one diastereomer C or

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