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Synthesis of Pyrrolizidine Derivatives by 1,3‐Dipolar Cycloaddition Reactions of Chiral Five‐Membered Cyclic Azomethine Ylides
Author(s) -
Argyropoulos Nikolaos G.,
Sarli Vasiliki C.,
Gdaniec Maria
Publication year - 2006
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200600207
Subject(s) - chemistry , azomethine ylide , pyrrolidine , cycloaddition , substituent , steric effects , pyrrolizidine , selectivity , ring (chemistry) , 1,3 dipolar cycloaddition , ring size , stereochemistry , medicinal chemistry , organic chemistry , catalysis
The 1,3‐dipolar cycloaddition reactions of chiral five‐membered cyclic azomethine ylides, generated in situ from ethyl glyoxylate and protected (3 S ,4 S )‐dihydroxypyrrolidines 3 and 6 have been studied. The facial selectivity of the cycloaddition reaction is governed by the steric effect of the substituent on the pyrrolidine ring next to the azomethine ylide functionality, leading in all cases to an exclusive Si face approach of the dipolarophile. The exo / endo selectivity depends on the dipolarophile and on the size of the other substituent on the pyrrolidine ring. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)