ISSN:
0947-3440
Keywords:
Asymmetric synthesis
;
N-Acyliminium ions
;
Camphor-derived chiral auxiliaries
;
2-Substituted piperidines
;
Enamides
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Asymmetric Electrophilic α-Amidoalkylation, 11. - New Chiral Auxiliaries from (+)-Camphoric AcidHerrn Professor Eberhard Reimann mit den besten Wünschen zum 60. Geburtstag gewidmet.The chiral bicyclic carboxylic acids 3b-e have been prepared in a few steps from camphoric acid. They were designed as new chiral auxiliaries for asymmetric synthesis with chiral N-acyliminium ions featuring precomplexation as a mechanism for asymmetric induction. Their asymmetric induction was evaluated in alkylation reactions with the enamides 5b-e being performed by addition of HCl and subsequent treatment of the resulting α-chloro amide with AlEt3. The carboxylic acid 3e turned out to be well suited as a chiral auxiliary providing high asymmetric induction (e.g. 92.9/7.1 with ZnEt2) and moderate chemical yields (66% 12e + 13e) and being easily removed by acid hydrolysis without destruction.
Additional Material:
2 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jlac.199619961130
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