Brief syntheses of (+)-blastmycinone and related γ-lactones from an asymmetrically dihydroxylated carboxylic ester
摘要:
A method for synthesizing optically active trans,trans-configurated alpha,beta,gamma-substituted gamma-lactones is presented. Asymmetric hydroxylation of ester 8 with AD mix alpha (AD mix beta) and subsequent dehydration provided butenolide S-6 (R-6). Conjugate addition of Li-2(Me2PhSi)(2)Cu(CN) to S-6 followed by alkylation of the resulting enolate led to the stereopure silyllactones 9-11. They furnished the title compounds after oxidative removal of the Me2PhSi group. (C) 1998 Elsevier Science Ltd. All rights reserved.
The reactivity of the title compounds with different nucleophiles has been checked and it was shown that products from reaction with sodium phenylthiolate result from an elimination-addition process in which protoanemonin is the key intermediate. The synthesis of (−)-(R)-β-angelica lactone is reported for the first time.
作者:Chao Lv、Qian Tu、Jianxian Gong、Xiaojiang Hao、Zhen Yang
DOI:10.1016/j.tet.2017.03.072
日期:2017.6
Asymmetrictotalsynthesis of (−)-perforanoid A, a novel limonoid isolated from the leaves of Harrisonia perforata, has been achieved. The key features of our totalsynthesis include the Rh-catalyzed intramolecular Pauson–Khand reaction of an allene and an alkene, the Pd-catalyzed lactonization of an allylic alcohol with a vinyl ether, and the enantioselective alkenylation of 3-furaldehyde.
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.
High pressure induced Diels-Alder cycloadditions of butenolides to electron-rich dienes
作者:Rosa M Ortuño、André Guingant、Jean d'Angelo
DOI:10.1016/s0040-4039(00)88496-8
日期:1988.1
β-Angelica lactone, a model of chiral butenolides, has been efficiently reacted with electron-rich dienes under high pressure conditions, with an excellent diastereofacial, regio- and endo-selectivity, giving the expected adducts in good yields. Some derivatives have been prepared.
Asymmetric Olefin Isomerization of Butenolides via Proton Transfer Catalysis by an Organic Molecule
作者:Yongwei Wu、Ravi P. Singh、Li Deng
DOI:10.1021/ja205674x
日期:2011.8.17
general olefin isomerization was realized via biomimetic protontransfer catalysis with a new chiral organic catalyst. A broad range of mono- and disubstituted β,γ-unsaturated butenolides were transformed into the corresponding chiral α,β-unsaturated butenolides in high enantioselectivity and yield in the presence of as low as 0.5 mol % catalyst. Mechanistic studies have revealed the protonation as the