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Synthesis of 3‐Fluorofuran‐2(5 H )‐ones Based on Z / E Photoisomerisation and Cyclisation of 2‐Fluoro‐4‐hydroxybut‐2‐enoates
Author(s) -
Pomeisl Karel,
Čejka Jan,
Kvíčala Jaroslav,
Paleta Oldřich
Publication year - 2007
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.200700439
Subject(s) - chemistry , fluoroacetate , ethyl ester , block (permutation group theory) , stereochemistry , medicinal chemistry , organic chemistry , biochemistry , geometry , mathematics
Mixtures of some ( E )‐ and ( Z )‐2‐fluoroalk‐2‐enoates prepared from the corresponding 2‐hydroxycarbonyl compounds and ethyl 2‐(diethoxyphosphoryl)‐2‐fluoroacetate have been transformed in high conversions into the target 3‐fluorofuran‐2(5 H )‐ones by an efficient Z / E photoisomerisation of noncyclisable Z isomers followed by acid‐catalysed cyclisation. In contrast, the acid‐catalysed deprotection of ethyl ( E )‐ and ( Z )‐4‐[ tert ‐butyl(dimethyl)silyloxy]‐2‐fluoro‐4‐phenylbut‐2‐enoates resulted in the displacement of vinylicfluorine, affording ethyl ( E )‐2‐oxo‐4‐phenylbut‐3‐enoate. 3‐Fluoro‐4‐phenylfuran‐2(5 H )‐one was transformed into 2‐[ tert ‐butyl(dimethyl)silyloxy]‐3‐fluoro‐5‐methylfuran as a novel fluorinated building block.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)