A CONVENIENT METHOD FOR THE SYNTHESIS OF 7-OXO-(<i>E</i>)-3-ALKENOIC ACIDS BY THE REACTION OF β-VINYL-β-PROPIOLACTONE WITH METALLATED<i>N</i>,<i>N</i>-DIMETHYLHYDRAZONES
作者:Tamotsu Fujisawa、Masashi Takeuchi、Toshio Sato
DOI:10.1246/cl.1982.1521
日期:1982.10.5
β-Vinyl-β-propiolactone reacts regio- and stereoselectively with an enolate equivalent such as cuprate derivatives of N,N-dimethylhydrazones and their bromomagnesium derivatives in the presence of a copper(I) catalyst to afford 7-oxo-(E)-3-alkenoic acids in high yields.
Synthesis of 3,6-dihydro-2H-pyran-2-ones via cationic palladium(II) complex-catalyzed tandem [2+2] cycloaddition-allylic rearrangement of ketene with α,β-unsaturated aldehydes and ketones
Treatment of ketene with α,β-unsaturated aldehydes and ketones in the presence of [Pd(dppb)(PhCN)2](BF4)2 leads to the formation of 4-vinyloxetan-2-ones, which rearrange under the conditions to give 3,6-dihydro-2H-pyran-2-ones in a variety of yields, depending on the substituents. Asymmetric induction with up to 57% de has been achieved by using α,β-unsaturated aldehydes bearing an asymmetric carbon
A NOVEL SYNTHESIS OF ROYAL JELLY ACIDS AND QUEEN SUBSTANCE BY THE FIVE CARBON HOMOLOGATION USING β-VINYL-β-PROPIOLACTONE
作者:Tamotsu Fujisawa、Toshio Sato、Toshiyuki Itoh
DOI:10.1246/cl.1982.219
日期:1982.2.5
10-Hydroxy-(E)-2-decenoic acid, (E)-2-decenedioic acid (Royal jelly acids), and 9-oxo-(E)-2-decenoic acid (queensubstance) were synthesized via 10-hydroxy-3-decenoic acid and 9,9-ethylenedioxy-3-decenoic acid, respectively, prepared easily by the regioselective ring-opening reaction of β-vinyl-β-propiolactone with Grignard reagents in the presence of copper(I) catalyst.
A SHORT-STEP SYNTHESIS OF (±)-PYRENOPHORIN UTILIZING 3-ALKENOATE AS A MASKED SYNTHON OF 4-OXO-2-ALKENOATE
作者:Tamotsu Fujisawa、Masashi Takeuchi、Toshio Sato
DOI:10.1246/cl.1982.1795
日期:1982.11.5
The use of 3-alkenoate as a maskedsynthon of 4-oxo-2-alkenoate was established by a three step conversion of 3-nonenoate into 4-oxo-2-nonenoate through epoxidation, isomerization to an allyl silyl ether, and oxidation in a high overall yield. This method was applied to the short step synthesis of pyrenophorin from 7-oxo-3-octenoic acid.
by the regio- and stereoselective ring opening of β, γ, and δ-lactones with unsaturated substituents at the ω-position using organocopperreagents such as halomagnesium diorganocuprates or Grignard reagents in the presence of copper(I) iodide. Both the organocopperreagents with primary, secondary, tertiary alkyl, and phenyl groups gave the corresponding carbon homologated alkenoic acids in good yields