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Synthesis of Spirocyclopropyl γ‐Lactams by a Highly Stereoselective Tandem Intramolecular Azetidine Ring‐Opening/Closing Cascade Reaction
Author(s) -
Nocquet PierreAntoine,
Hazelard Damien,
Compain Philippe
Publication year - 2011
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.201101278
Subject(s) - azetidine , chemistry , stereoselectivity , intramolecular force , cascade reaction , ketene , stereochemistry , alkylation , nucleophile , ring (chemistry) , intramolecular reaction , medicinal chemistry , organic chemistry , catalysis
A new tandem intramolecular azetidine ring‐opening/closing cascade reaction affording spirocyclopropyl γ‐lactams in high regio‐ and stereoselectivity is reported. The key step of the process is an S N 2‐type ring‐opening of TMSOTf‐activated azetidine rings by silyl ketene acetals generated by treatment with TMSOTf and triethylamine. This study is a very rare example of nucleophilic ring opening of azetidines that does not require formation of quaternary azetidinium salts by N ‐alkylation or the use of N ‐electron‐withdrawing groups.