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Stereoselectivity in formation of oxacephams from 1,3‐alkylidene‐threitols
Author(s) -
Borsuk Katarzyna,
Grzeszczyk Barbara,
Szczukiewicz Patrycja,
Przykorska Beata,
Frelek Jadwiga,
Chmielewski Marek
Publication year - 2004
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.20058
Subject(s) - chemistry , stereoselectivity , stereochemistry , organic chemistry , catalysis
The [2+2]cycloaddition of CSI to the ( Z )‐propenyl ethers derived from respective 1,3‐methylidene‐ and 1,3‐ethylidene‐threitols, contrary to the corresponding erythritol derivatives, is characterized by a low stereoselectivity and a lack of stereospecificity. On the other hand, the alternative method of the oxacepham formation, based on the 4‐vinyloxy‐azetidinone, proceeds with an excellent stereoselectivity. The CD‐spectroscopy offers an attractive tool for determination of the absolute configuration of the bridgehead carbon atom at the 5‐oxacepham skeleton. Chirality 16:414–421, 2004. © 2004 Wiley‐Liss, Inc.