Generation of Oxozirconocene Complexes from the Reaction of Cp<sub>2</sub>(THF)ZrN-<i>t</i>-Bu with Organic and Metal Carbonyl Functionalities: Apparently Divergent Behavior of Transient [Cp<sub>2</sub>ZrO]
作者:Sun Yeoul Lee、Robert G. Bergman
DOI:10.1021/ja954050t
日期:1996.1.1
Cp2(THF)ZrN-t-Bu (1a) toward a series of organic and metal carbonyl complexes has been examined. The ZrN linkage of 1a undergoes imido/oxo exchange reactions with the carbonylcompounds and generates three different types of oxozirconocene products: (Cp2ZrO)n (3), (Cp2Zr)2(μ-O)(μ-N-t-Bu) (9), and (Cp2Zr)2O3CCPh2 (12) were obtained from the reactions of 1a with RR‘CO (R = R‘ = Me (2b); R = Ph, R‘ = H (2c);
已经检查了 Cp2(THF)ZrN-t-Bu (1a) 对一系列有机和金属羰基配合物的反应性。1a 的 ZrN 键与羰基化合物发生亚胺/氧代交换反应并生成三种不同类型的氧代锆茂产物:(Cp2ZrO)n (3)、(Cp2Zr)2(μ-O)(μ-Nt-Bu) (9 ), 和 (Cp2Zr)2O3CCPh2 (12) 是从 1a 与 RR'CO 的反应中获得的 (R = R' = Me (2b); R = Ph, R' = H (2c); R = i-Pr, R' = H (2d))、CpCo(CO)2 (7) 和 Ph2CCO (10)。这些反应中的副产物分别是亚胺 RR'CN-t-Bu (4b-d)、异腈配合物 CpCo(CO)(CN-t-Bu) (8a) 和烯酮亚胺 Ph2CCN-t-Bu (11a)。随着含有α-氢原子的更多受阻羰基,反应遵循不同的途径,导致形成烯醇配合物Cp2Zr(NH-t-Bu)(OCR3CR2R1)
Preparation of 1,2,5-Trisubstituted 1<i>H</i>-Imidazoles from Ketenimines and Propargylic Amines by Silver-Catalyzed or Iodine-Promoted Electrophilic Cyclization Reaction of Alkynes
作者:Xiaorong Zhou、Zheng Jiang、Lexing Xue、Ping Lu、Yanguang Wang
DOI:10.1002/ejoc.201500704
日期:2015.9
From readily available propargylic amines, 1,2,5-trisubstituted imidazoles are efficiently obtained through a cascade reaction catalyzed by AgOTf or promoted by molecular iodine. The AgOTf-catalyzed reaction involves nucleophilic addition of propargylic amine to ketenimine, a silver-catalyzedelectrophiliccyclizationreaction of alkyne, and a tautomerism/isomerism/metal-H exchange cascade. The iodine-mediated
Rh-Catalyzed annulations of N-methoxybenzamides with ketenimines: synthesis of 3-aminoisoindolinones and 3-diarylmethyleneisoindolinones with strong aggregation induced emission properties
作者:Xiaorong Zhou、Zhixing Peng、Hongyang Zhao、Zhiyin Zhang、Ping Lu、Yanguang Wang
DOI:10.1039/c6cc05456k
日期:——
Rhodium-catalyzed C–H activation/annulation reactions of ketenimines with N-methoxybenzamides furnished 3-aminoisoindolin-1-ones and 3-(diarylmethylene)isoindolin-1-ones.
Compounds of formula (I) which exhibit excellent immune suppression activity, pharmacologically acceptable salts thereof, esters thereof or other derivatives:
1
wherein R
1
and R
2
are a hydrogen atom, an amino protecting group; R
3
is a hydrogen atom, a hydroxy protecting group; R
4
is a lower alkyl group; n is an integer from 1 to 6; X is an ethylene group; Y is a C
1
-C
10
alkylene group, a C
1
-C
10
alkylene group substituted with 1 to 3 substituents selected from substituent group a and b; R
5
is an aryl group; R
6
and R
7
are a hydrogen atom, a group selected from substituent group a; with the proviso when R
5
is a hydrogen atom, Y is not a single bond or a straight chain C
1
-C
10
alkylene group.
Cardiac glycosides: 5. Stereoselective syntheses of digitoxigenin α-D, β-D, α-L, and β-L-glucosides
作者:Hargovind Rathore、Toshihiro Hashimoto、Kikuo Igarashi、Haruo Nukaya、Dwight S. Fullerton
DOI:10.1016/s0040-4020(01)91342-0
日期:1985.1
As part of a continuing study of cardiac g1ycos1des,1,2 stereoselectivesyntheses of the four possible glucosides of digitoxigenin were developed via the thermodynamically produced tetra-O-benzyl-D- and L-glucosyl α-trichloroacetaimidates 2α and 11α, and the kinetically produced β-trichloroacetaimidates 2β and 11β. A 58%:19% isolated yield ratio of α-D and β-D benzyl protected glycosides 6 and 3 could