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
Pd-catalyzed 5-endo-trig-type cyclization of β,γ-unsaturated carbonyl compounds: an efficient ring closing reaction to give γ-butenolides and 3-pyrrolin-2-ones
作者:Gan B. Bajracharya、Priti S. Koranne、Rashid N. Nadaf、Randa Kassem Mohamed Gabr、Kazuhiro Takenaka、Shinobu Takizawa、Hiroaki Sasai
DOI:10.1039/c0cc02352c
日期:——
The 5-endo-trig-type cyclization has been performed using a Pd-bis(isoxazoline) catalyst. The present cyclization of beta,gamma-unsaturated carbonylcompounds gave gamma-butenolides and 3-pyrrolin-2-ones in good to excellent yields.
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.
Abstract The combination of dimethylsulfoxide and oxalyl bromide was used to accomplish the cyclization of 3-alkenoic acids with the aid of a base to afford γ-butenolides, in which bromodimethylsulfonium salt generated in situ was proposed to serve as a Br+ source. GRAPHICAL ABSTRACT