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Ring‐Closing Metathesis of Vinyl Fluorides towards α‐Fluorinated α,β‐Unsaturated Lactams and Lactones
Author(s) -
Marhold Michael,
Stillig Christian,
Fröhlich Roland,
Haufe Günter
Publication year - 2014
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.201402535
Subject(s) - chemistry , ring closing metathesis , yield (engineering) , metathesis , double bond , ring (chemistry) , medicinal chemistry , indolizidine , lactam , olefin fiber , catalysis , organic chemistry , stereochemistry , materials science , metallurgy , polymerization , alkaloid , polymer
Ring‐closing olefin metathesis reactions (RCM) using Grubbs II or Hoveyda's catalysts have been applied to a series of N ‐alkenyl‐ N ‐benzyl‐α‐fluoroacrylamides. α‐Fluoro‐α,β‐unsaturated γ‐ or δ‐lactams incorporating a fluorinated double bond were obtained in moderate to good yields, depending on the nature of substituents on the benzyl ring. The corresponding seven‐ and eight‐membered lactams were not formed under similar conditions. When the N ‐benzyl group was replaced by an N ‐tosyl group, the corresponding ϵ‐lactam was also formed in 38 % yield. When N ‐(2‐fluoroallyl) derivatives were used instead of fluoroacryloyl derivatives, six‐, seven‐, and eight‐membered N‐heterocycles were obtained in low yields. This method was also used to synthesize fluorinated α,β‐unsaturated analogues of pyrrolizidine and indolizidine alkaloids from prolinol, and also to synthesize N ‐benzyl‐3‐fluoroquinolone in three steps from commercially available 2‐vinylaniline in 44 % overall yield. Also 3‐fluorocoumarin and 3‐fluorochromene were prepared from o ‐vinylphenol, and 3‐fluoro‐benzoxepine was available from o ‐allylphenol.