ISSN:
0947-3440
Keywords:
Amino alcohols
;
Chiral α-amino carbanions
;
Diastereoselective α-aminoalkylation
;
Proline analogues
;
Enantioselective borane reduction
;
Chiral auxiliaries
;
Waste prevention
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
New, chiral β-sec-amino alcohols 3a-d, 4a-e, and 5a-h have been synthesized from the enantiomerically pure amine (all-R)-2a. For the diastereo- and regioselective α-hydroxyalkylation of the chiral (all-R)-N-nitroso-2-azabicyclo[3.3.0]octane (all-R)-2d, Seebach's “one pot” method was chosen. The versatile nucleophilic intermediate reacts regio-and stereoselectively with a variety of electrophiles to afford 3-substituted pyrrolidine derivatives, e.g. (erythro)-(αR,βS)-amino alcohol frameworks with four sterically crowded stereogenic centers, and (βS)-configured tricyclic structures with a cycloalkynol building block (see formulae 3a-d, 4a-e, and 5a-h). Alkylation products are obtained in fair yields with a high degree of stereoselectivity (diastereomeric ratios dr up to 93:7). A mechanistic interpretation of the stereochemical course of this reaction is presented. - This is a further example of the synthesis of interesting new chiral ligands from the industrial waste material (all-R)-2-azabicyclo[3.3.0]octane-3-carboxylic acid benzyl ester (all-R)-1a. The catalytic ability of selected (erythro)- and new, related stereoisomeric amino alcohol structures were tested in the enantioselective borane reduction using the prochiral acetophenone as model substrate (enantiomeric excesses ee up to 86%).
Additional Material:
8 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jlac.199719970318
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