Selective Activation/Coupling of Polyhalogenated Nucleophiles in Ni/Cr-Mediated Reactions: Synthesis of C1–C19 Building Block of Halichondrin Bs
摘要:
The C1-C19 building block 46 of halichondrin Bs was synthesized via a selective activation/coupling of beta-bromoenone 34 with aldehyde 35 in a Ni/Cr-mediated reaction. The first phase of study was a method development to effect a coupling of a naked vinylogous anion with an aldehyde. The study with the coupling of 9 + 10 -> 11 revealed: (1) beta-bromoenone 9b is a better nucleophile than the corresponding beta-iodo- and beta-chloroenones 9a,c; (2) (Me)(2)Phen(OMe)(2)center dot NiCl2 13b is a better Ni-catalyst than (Me)(2)Phen(H)(2)center dot NiCl2 13a; and (3) a low Ni-catalyst loading, for example, 0.05-0.1 mol % Ni-catalyst against 10 mol % Cr-catalyst, is crucial for an effective coupling. The second phase of study was a method development to realize a selective activation/coupling of polyhalogenated nucleophiles such as 34. The competition experiment of 10 + 9b over 10 + 31a-c revealed: (1) (Me)(2)Phen(OMe)(2)center dot NiCl2 13b is more effective than (Me)(2)Phen(H)(2)center dot NiCl2 13a for the required selective activation/coupling; (2) a low Ni-catalyst loading, for example, 0.05-0.1 mol % Ni-catalyst against 10 mol % Cr-catalyst, is crucial for discriminating beta-bromoenone 9b from the three types of vinyl iodides 31a-c. The third phase of study was an application of the developed method to execute the proposed coupling of 34 + 35 -> 36. For this application, a polyether-type Ni-catalyst 37c, readily soluble in the reaction medium, was introduced to achieve the selective activation/coupling with higher efficiency. With use of ion-exchange resin-based device, the coupling product 36 was transformed to the C1-C19 building block 46 of halichondrin Bs without purification/separation of the intermediates.
CX (X=Br, I) Bond-Tolerant Aerobic Oxidative Cross- Coupling: A Strategy to Selectively Construct β-Aryl Ketones and Aldehydes
作者:Mao Chen、Jie Wang、Ziyi Chai、Cai You、Aiwen Lei
DOI:10.1002/adsc.201100782
日期:2012.2
aryl halide-containing β-aryl ketones and aldehydes can be synthesized directly from readily available allyic alcohols and boronic acids via palladium-catalyzedoxidativecross-coupling reactions. The dual roles of copper, including electron-carrier and Lewis acid functions, are supposed to be critical for the high reactivity and selectivity of this aerobic oxidative coupling transformation.
Heck arylation of allyl alcohol catalyzed by Pd(0) nanoparticles
作者:Stanisława Tarnowicz、Waleed Alsalahi、Ewa Mieczyńska、Anna M. Trzeciak
DOI:10.1016/j.tet.2017.03.034
日期:2017.9
Pd(OAc)2 in water at 80 °C in the presence of a PVP-stabilizing polymer. Pd(0) NPs were successfully used in the Heckcoupling of allyl alcohol with iodo- and bromobenzenes. Iodobenzenes reacted under solventless conditions or in DMF solution producing 3-arylpropanals and 2-arylpropanals as the main products. The same products were obtained in the reaction of bromobenzene in TBAB as the reaction medium
By using a heterobimetallic catalyst, (CO)4(PEtPh2)W(μ-PPh2)Rh(CO)(PPh3), chemoselective hydroformylation of monosubstituted alkenes proceeds efficiently at room temperature under atmospheric pressure of CO/H2, without affecting functional groups such as disubstituted alkene moieties, aryl and alkenyl iodide moieties, and hydroxy and carboxy groups.
[EN] CARBOSTYRIL COMPOUND<br/>[FR] DÉRIVÉ DE CARBOSTYRILE
申请人:OTSUKA PHARMA CO LTD
公开号:WO2006035954A1
公开(公告)日:2006-04-06
The present invention provides a carbostyril compound represented by General Formula (1) or a salt thereof, wherein A is a direct bond, a lower alkylene group, or a lower alkylidene group; X is an oxygen atom or a sulfur atom; R4 and R5 each represent a hydrogen atom; the bond between the 3 and 4 positions of the carbostyril skeleton is a single bond or a double bond; R1 is a hydrogen atom, etc; R2 is a hydrogen atom, etc; and R3 is a hydrogen atom, etc. The carbostyril compound or salt thereof of the present invention induces the production of TFF, and thus is usable for the treatment and/or prevention of disorders such as alimentary tract diseases, oral diseases, upper respiratory tract diseases, respiratory tract diseases, eye diseases, cancers, and wounds.