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Diastereo‐ and enantioselective synthesis of 1,2:5,6‐diepoxy‐4‐hydroxyalkyl carbamates. – regioselective ring opening and their transformation into doubly C ‐branched deoxy sugar analogues
Author(s) -
Peschke Bernd,
Lüßmann Jörg,
Hoppe Dieter,
Dyrbusch Zzmichael
Publication year - 1992
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19921250620
Subject(s) - chemistry , enantioselective synthesis , regioselectivity , nucleophile , ring (chemistry) , stereochemistry , reagent , alkyl , organic chemistry , catalysis
Enantiomerically enriched (Z)‐ anti ‐3,5‐dialkyl‐4‐hydroxy‐1,5‐alkadienyl N,N ‐diisopropylcarbamates 12 , readily obtained by the homoaldol approach, were oxidized with essentially complete diastereoselectivity to afford 1,2:5,6‐diepoxides 14 of D‐ allo configuration. Conditions were worked out for the transformation of 14 into furanosides of types 19, 21 , and 22 and for the selective nucleophilic introduction of carbon residues into the 6‐position to give chain‐elongated analogues 25 . Altogether, a “brick‐box system” for the enantioselective construction of polystereogenic building blocks with a few synthetic steps from simple achiral starting materials [( E )‐2‐alkenyl carbamates of type 9 and 2‐alkyl‐2‐alkenals ( 11 )] and nucleophiles, like Grignard reagents, is demonstrated.