A general synthesis of 2- or 3-alkyl substituted 5-hydroxymethyl-δ-valerolactones, precursors of 5-formyl-δ-valerolactones, via lithiated N-allyl(bisdimethylamino)-N-methylphosphoramide carbanions
摘要:
A convenient strategy is reported for the synthesis of 2- or 3-alkylsubstituted 5-hydroxymethyl and 5-formyl-delta-valerolactones, which are very useful starting blocks for the total synthesis of leukotrienes and lactonic pheromones, It has been found that lithiated enephosphoramide ambident anions reacted exclusively in the gamma position with 2,3-O-isopropylidene glycerol triflate to give corresponding alkylated enephosphoramides by a C3-C3 backbone connection. Enephosphoramide group was further selectively hydrolyzed in the presence of isopropylidene function in mild acidic conditions and led to expected aldehydes in high yields. Oxidation of these aldehydes using silver oxide or potassium permanganate afforded corresponding acids. Further hydrolysis of the isopropylidene group led to unstable dihydroxyacids which directly lactonized. The latter were converted to 5-formyl-delta-valerolactones using PDC oxidant. (C) 1999 Elsevier Science S.A. All rights reserved.
A general synthesis of 2- or 3-alkyl substituted 5-hydroxymethyl-δ-valerolactones, precursors of 5-formyl-δ-valerolactones, via lithiated N-allyl(bisdimethylamino)-N-methylphosphoramide carbanions
摘要:
A convenient strategy is reported for the synthesis of 2- or 3-alkylsubstituted 5-hydroxymethyl and 5-formyl-delta-valerolactones, which are very useful starting blocks for the total synthesis of leukotrienes and lactonic pheromones, It has been found that lithiated enephosphoramide ambident anions reacted exclusively in the gamma position with 2,3-O-isopropylidene glycerol triflate to give corresponding alkylated enephosphoramides by a C3-C3 backbone connection. Enephosphoramide group was further selectively hydrolyzed in the presence of isopropylidene function in mild acidic conditions and led to expected aldehydes in high yields. Oxidation of these aldehydes using silver oxide or potassium permanganate afforded corresponding acids. Further hydrolysis of the isopropylidene group led to unstable dihydroxyacids which directly lactonized. The latter were converted to 5-formyl-delta-valerolactones using PDC oxidant. (C) 1999 Elsevier Science S.A. All rights reserved.
5-formyl-δ—valerolactone : A useful synthon for the chiral synthesis of the vespa orientalis pheromone and the mosquito oviposition attractant pheromone
作者:Ph. Coutrot、C. Grison、C. Bômont
DOI:10.1016/s0040-4039(00)74412-1
日期:1994.11
A synthetic scheme starting from the reaction between the lithiated N-allyl-N-methyl-(bisdimethylamino)phosphoramide anion and the triflate derivative of (R)-(-)- or (S)-(+)-2,3-O-isopropylideneglycerol is described to prepare the key chiral synthon (R)-5- or (S)-5-formyl-delta-valerolactone that leads to the title compounds.