SELECTIVE REACTIONS OF THIOLATE ANIONS WITH 4-HYDROXY-E-2-ALKENOIC ESTERS OR 4-METHANESULFONYLOXY-E-2-ALKENOIC ESTERS. SYNTHESIS OF 2-ALKEN-4-OLIDES (Δα,β-BUTENOLIDES) ANDE,E-2,4-ALKADIENOIC ESTERS
SELECTIVE REACTIONS OF THIOLATE ANIONS WITH 4-HYDROXY-E-2-ALKENOIC ESTERS OR 4-METHANESULFONYLOXY-E-2-ALKENOIC ESTERS. SYNTHESIS OF 2-ALKEN-4-OLIDES (Δα,β-BUTENOLIDES) ANDE,E-2,4-ALKADIENOIC ESTERS
electrophiles including alkyl halides, carbonyl compounds, and sodium iodoacetate. A convenient synthetic method for 4-alkyl- and 5-alkyl-2(5H)-furanones has been developed by using these dianions. A new synthetic approach to trans-3,4-bis(3-hydroxybenzyl)dihydro-2(3H)-furanone, the first lignan found in humans, via a facile reduction of 2(5H)-furanone with Mg-methanol is also decribed.
Treatment of N-phenyl-3-(phenylsulfonyl)propanamide with 2 equiv. of butyllithium at −78 °C afforded the dianion. Aldehydes and ketones upon treatment with the dianion provided stable γ-hydroxy amides, which were converted in good yields to 5-alkyl-2(5H)-furanones. Optically active (R)- and (S)-5-octyl-2(5H)-furanones, and (R)- and (S)-5-tridecyl-2 (5H)-furanones were prepared from aldehydes and the dianions, derived from chiral N-monosubstituted-3-(phenylsulfonyl)propanamides.