α-苯硫醛可以使用简单的多步骤程序轻松制备,本文中将其作为 NHC 催化生成酰基唑鎓和烯醇化唑鎓中间体的新前体引入,这些中间体具有广泛的合成兴趣和实用性。用 NHC 预催化剂和碱处理 α-苯硫醛,通过Breslow 中间体产生有效的氧化还原重排,消除苯硫酚盐,随后回弹加成至生成的酰基唑鎓,得到相应的硫羟酸酯。在外部醇存在的情况下,氧化还原重排和氧化还原酯化之间的竞争可以通过明智地选择NHC预催化剂内的N-芳基取代基和反应中使用的碱来控制。以NEt 3为基体,带有吸电子( N -C 6 F 5或N -C 6 H 2 Cl 3 )取代基的NHC有利于氧化还原重排,而带有富电子N-芳基取代基( N -Ph, N )的三唑鎓预催化剂-Mes) 导致优先氧化还原酯化。使用DBU时,由于最初形成的硫羟酸酯产物发生酯交换反应,因此优选氧化还原酯化反应。此外,α-苯硫醛衍生的唑鎓烯醇化物已用于对映选择性形式[4
The reaction of singlet oxygen with tetrakis(ethylthio)ethylene has been shown to afford diethylthiooxalate and diethyl disulfide. The expected diethylthiocarbonate was also obtained as a minor product. A similar reaction with bis(ethylthio)ethylene gave ethylthioglyoxalate together with diethyl disulfide. Formation of diethylthioacetaldehyde was also observed, and is suggested to proceed via the intermediary
Heterocyclic synthesis by CC bond formation. Tetrahydrofuran and tetrahydropyran synthesis via oxonium ion-mediated cyclisation reactions
作者:Donald Craig、N.Paul King、Antony N. Shaw
DOI:10.1016/s0040-4039(97)10294-5
日期:1997.12
Dimethyl(methylthio)sulfonium tetrafluoroborate triggers ionisation and cyclisation of hemithioacetals 3 to give tetrahydrofurans 8–11 in good yields and stereoselectivities. The homologous sulfone analogues 17 give tetrahydropyrans on treatment with ethylaluminium dichloride.
Diastereoselection during 1,2-Addition of the Allylindium Reagent to α-Thia and α-Amino Aldehydes in Aqueous and Organic Solvents
作者:Leo A. Paquette、Thomas M. Mitzel、Methvin B. Isaac、Curtis F. Crasto、William W. Schomer
DOI:10.1021/jo970274d
日期:1997.6.1
The stereochemistry of the indium-promoted reaction of allyl bromide with alpha-thia (PhS and MeS), disubstituted alpha-amino (Bn2N, Me2N, isoindolyl), and protected alpha-amino aldehydes (Ac and Boc) in water has been evaluated. The reactions involving the sulfur derivatives are minimally diastereoselective, indicating that the allylindium reagent is not thiophilic. Chelation is not observed and pi-facial discrimination is achieved via Felkin-Ahn transition states under the steric control of the substituents. The Garner aldehyde is also anti-diastereoselective. Interestingly, N-acetylmannosamine is appreciably responsive to chelation control and is capable of generating 90% of the syn beta-amino alcohol when reacted in a 0.5 M NH4Cl solution. While the alpha-dibenzylamino substituent is too bulky to enter into complexation, the alpha-dimethylamino group is not and can lead to high levels (99%) of syn diastereomer. The size of other neighboring substituents does have an impact on pi-facial discrimination in these systems and can erode the stereoselectivity accordingly.
N-ACYLSULFONAMIDE APOPTOSIS PROMOTERS
申请人:Abbott Laboratories
公开号:EP1318978A2
公开(公告)日:2003-06-18
[EN] N-ACYLSULFONAMIDE APOPTOSIS PROMOTERS<br/>[FR] PROMOTEURS DE L'APOPTOSE A BASE DE N-ACYLSULFONAMIDES
申请人:ABBOTT LAB
公开号:WO2002024636A2
公开(公告)日:2002-03-28
N-Benzoyl arylsulfonamides having the formula (I) are BCL-Xl inhibitors and are useful for promoting apoptosis. Also disclosed are BCL-Xl inhibiting compositions and methods of promoting apoptosis in a mammal.