The [2,3]Wittig rearrangement of 2-alkenyloxyacetic acids and its applications to the stereocontrolled synthesis of β, γ-unsaturated aldehydes and conjugated dienoic acids
Dianions generated from 2-alkenyloxyacetic acids readily undergo the [2,3]sigmatropic rearrangement uhich can constitute the versatile synthetic sequences for the stereocontrolled synthesis of β,γ-unsaturated aldehydes and conjugated dienoic acids.
A novel silyl triflate-mediated [2,3]sigmatropicrearrangement of (allyloxy)acetates and their ketene silyl acetals is described, which is proposed to proceed via rarely precedented oxygen ylides. The formal [2,3]Wittlg shift is characterized by the unique stereoselectivity, , the rarely precedented -selectivity and the high erythro-selectivity.
Compositions and methods for improving the quality of chemically treated hair
申请人:L'OREAL
公开号:US11135150B2
公开(公告)日:2021-10-05
The present disclosure relates to hair care compositions for chemically treating hair, to kits comprising the compositions, and to methods for treating hair with the compositions. The compositions include one or more polymeric acid compounds and/or polymeric acid anhydride compounds in addition to one or more active agents for chemically treating the hair. Additionally, the compositions can optionally include one or more non-polymeric, mono-, di-, and/or tri-carboxylic acids and/or one or more mono- and/or di-amines and/or polyamines. Hair treated with the compositions exhibits improved softness, smoothness, and discipline.
[2,3]-Wittig rearrangement of allylic glycolate esters via boron and tin enolates
作者:Taeboem Oh、Zbigniew Wrobel、Steven M. Rubenstein
DOI:10.1016/s0040-4039(00)92271-8
日期:1991.1
Wittig rearrangement of allylic glycolate esters via boron and tin enolates gave diastereoselectivities as high as 99.5 : 0.5. Tin enolates were more stereoselective than boron enolates.
[2,3]-Wittig rearrangement of γ-allyloxy-β-ketoesters. A new access to tetronic acids
作者:Isabelle Pévet、Christophe Meyer、Janine Cossy
DOI:10.1016/s0040-4039(01)00982-0
日期:2001.7
Dilithiated gamma -allyloxy-beta -ketoesters undergo a [2,3]-Wittig rearrangement leading to protected gamma -hydroxy-beta -ketoesters, which can be converted to tetronic acids. (C) 2001 Elsevier Science Ltd. All rights reserved.