Abstract For understanding the mechanism involved in the Wittigreaction, it is important to know the factors which influence the stability of 1,2-oxaphosphetane intermediates with pentacoordinate phosphorus; in these intermediates, the steric factor plays a predominant role. Studying the Wittigreaction between nonstabilized ylides and different aldehydes, we noted that the stereochemical outcome
Studies of Stereo-Selective Cyclo-Additions and Transformations of Substituted 2-Cyclopenten-1-one with Chiral Anthracene Templates.
作者:Weerachai Phutdhawong、Gedsirin Eksinitkun、Yonlada Jaroensuk、Anthony C. Willis、Waya S. Phutdhawong
DOI:10.13005/ojc/330601
日期:2017.12.28
The chiral (S)-9-(1-methoxyethyl), (R)-9-(1,2-dimethoxyethyl) and 9-(1R, 2R)-(1,2dimethoxypropyl) anthracenes were synthesised and used for the thermal Diels-Alder reaction with cyclopentene-3,5-dione. Unlike the maleic anhydride and N-substituted malemides, the cyclo-adducts were obtained with high regio-selectivity as a single diastereomer. The X-ray structure of the cyclo-adduct showed an enol form
合成了手性(S)-9-(1-甲氧基乙基),(R)-9-(1,2-二甲氧基乙基)和9-(1R,2R)-(1,2二甲氧基丙基)蒽,并将其用于热狄尔斯-与环戊烯-3,5-二酮的Al醛反应。与马来酸酐和N-取代的马来酰亚胺不同,以高区域选择性作为单个非对映异构体获得了环加合物。环加合物的X射线结构显示为烯醇形式,但13 C NMR显示两个环戊酮羰基的共振,表明溶液结构为二酮形式。使用羰基基团上的有机镁加成物进行的立体控制研究导致烯醇醚的水解裂解并消除了水,从而得到α-烷基酮蒽加合物。这些在制备手性环戊烯酮核心结构中没有成功。
Neutral Ionic Liquid [hmim]Br as a Green Reagent and Solvent for the Mild and Efficient Dehydration of Benzyl Alcohols into (<i>E</i>)-Arylalkenes Under Microwave Irradiation
作者:Rakesh Kumar、Abhishek Sharma、Naina Sharma、Vinod Kumar、Arun K. Sinha
DOI:10.1002/ejoc.200800657
日期:2008.11
A mild and efficient, ionic-liquid-assisted, green protocol for the dehydration of benzyl alcohols into the corresponding (E)-arylalkenes under microwave irradiation has been developed. The method utilizes a neutral and recyclable ionic liquid (1-hexyl-3-methylimidazolium bromide) as a reagent and solvent to cleanly provide a wide range of olefins withoutthe need of harsh and expensive Bronsted/Lewis
Aromatic sulphonation. Part 74. Sulphonation of some 9-alkenylanthracenes and the corresponding benzenes with dioxan–SO<sub>3</sub>
作者:Freek van de Griendt、Hans Cerfontain
DOI:10.1039/p29800000023
日期:——
The sulphonation of six alkenylarenes with dioxan–SO3 in dioxan has been studied at 17 °C. With the substrates 9-vinyl-(3a), 9-(prop-2-enyl)-(3b), and 9-[(E)-but-2-enyl]-anthracene (3c), and (E)-prop-1- and -2-enylbenzene (3d and e) unsaturated pyrosulphonic acids are obtained with the double bond at C-α and the pyrosulphonic acid group at C-β- for the substrates (3a, b, d, and e), and the double bond
已经在17°C下研究了在二恶烷中用二恶烷– SO 3磺化六种烯基芳烃的方法。具有底物9-乙烯基-(3a),9-(丙-2-烯基)-(3b)和9-[(E)-丁-2-烯基]-蒽(3c)和(E)-获得了用于底物(3a,b,d和e)的具有C-α双键和位于C-β-的焦磺酸基团的丙-1-烯丙基和丙烯基(3d和e)不饱和焦磺酸对于(1c),C-β处的双键和C- γ处的焦磺酸基团。除了少量的上述焦磺酸外,丙-2-烯基衍生物(3b和e)还产生主要为2-芳基丙-1-烯-3-磺酸的底物(3d),顺式和反式为底物(3d)。-环状磺酸盐磺酸酐的异构体(5d)。所有这些磺基产物都是由于SO 3对侧链双键的直接攻击而产生的。9-[(E)-丙-1-烯基]蒽产生的主要产物为(E)-1-(9-蒽基)丙-1-烯-3-磺酸钠。提示该产物是由SO 3在蒽基10位上的初始进攻所致,随后是先前论文中提出的反应顺序。将当前研究的蒽衍生物的