118474-94-5Relevant academic research and scientific papers
Molecular Engineering of β-Substituted Oxoporphyrinogens for Hydrogen-Bond Donor Catalysis
Chahal, Mandeep K.,Payne, Daniel T.,Matsushita, Yoshitaka,Labuta, Jan,Ariga, Katsuhiko,Hill, Jonathan P.
supporting information, p. 82 - 90 (2020/01/02)
A new class of bifunctional hydrogen-bond donor organocatalyst using oxoporphyrinogens having increased intramolecular hydrogen-bond donor distances is reported. Oxoporphyrinogens are highly non-planar rigid macrocycles containing a multiple hydrogen bond-forming binding site. In this work, we describe the first example of non-planar OxPs as hydrogen-bond donor catalysts prepared using a molecular engineering approach of the binding site for dual activation of substrates. The introduction of β-substituents is key to the catalytic activity and the catalysts are able to catalyze 1,4-conjugate additions and sulfa-Michael additions, as well as, Henry and aza-Henry reactions at low catalyst loadings (≤ 1 mol-%) under mild conditions. Preliminary mechanistic studies have been carried out and a possible reaction mechanism has been proposed based on the bi-functional activation of both substrates through hydrogen-bonding interactions.
Novel total syntheses of oxoaporphine alkaloids enabled by mild Cu-catalyzed tandem oxidation/aromatization of 1-Bn-DHIQs
Zheng, Bo,Qu, Hui-Ya,Meng, Tian-Zhuo,Lu, Xia,Zheng, Jie,He, Yun-Gang,Fan, Qi-Qi,Shi, Xiao-Xin
, p. 28997 - 29007 (2018/08/29)
Novel total syntheses of oxoaporphine alkaloids such as liriodenine, dicentrinone, cassameridine, lysicamine, oxoglaucine and O-methylmoschatoline were developed. The key step of these total syntheses is Cu-catalyzed conversion of 1-benzyl-3,4-dihydro-isoquinolines (1-Bn-DHIQs) to 1-benzoyl-isoquinolines (1-Bz-IQs) via tandem oxidation/aromatization. This novel Cu-catalyzed conversion has been studied in detail, and was successfully used for constructing the 1-Bz-IQ core.
β-selective C-H arylation of pyrroles leading to concise syntheses of lamellarins C and I
Ueda, Kirika,Amaike, Kazuma,Maceiczyk, Richard M.,Itami, Kenichiro,Yamaguchi, Junichiro
supporting information, p. 13226 - 13232 (2015/03/30)
The first general β-selective C-H arylation of pyrroles has been developed by using a rhodium catalyst. This C-H arylation reaction, which is retrosynthetically straightforward but results in unusual regioselectivity, could result in de novo syntheses of
Enantioselective synthesis of 1-vinyltetrahydroisoquinolines via Pd-catalyzed intramolecular asymmetric allylic amination reactions
Chien, Chih-Wei,Shi, Ce,Lin, Chi-Feng,Ojima, Iwao
experimental part, p. 6513 - 6523 (2011/09/20)
1-Vinyltetrahydroisoquinolines serve as versatile intermediates for the synthesis of a variety of naturally occurring isoquinoline alkaloids. 1-Vinyl-6,8-dimethoxytetrahydroisoquinoline 4 and 1-vinyl-5,6,7- trimethoxytetrahydroisoquinoline 6 with >90% ee by means of Pd-catalyzed intramolecular asymmetric allylic amination reactions, using MPN and BOP ligands, developed in our laboratory. The fine-tuning capability of the MPN and BOP ligands has played a significant role in the optimization of enantioselectivity. Interesting substituent effect as well as solvent effect on the product selectivity and enantioselectivity was observed. Plausible mechanisms are proposed, which can accommodate various findings, including the critical importance of the activation of the trifluoroamide moiety through its coordination to the Lewis acidic Pd2+ metal center.
Biomimetic total synthesis of (±)-8-oxoerymelanthine
Yoshida, Yuki,Mohri, Kunihiko,Isobe, Kimiaki,Itoh, Toshimasa,Yamamoto, Keiko
supporting information; experimental part, p. 6010 - 6015 (2009/12/08)
(Chemical Equation Presented) Erymelanthine 1 and 8-oxoerymelanthine 2 are unique erythrina alkaloids containing a pyridine ring. We synthesized (±)-8-oxoerymelanthine 2 in 2.0% overall yield using the following key reactions. The characteristic 6-5-6-6-m
Total synthesis of natural and unnatural lamellarins with saturated and unsaturated D-rings
Ploypradith, Poonsakdi,Petchmanee, Thaninee,Sahakitpichan, Poolsak,Litvinas, Nichole D.,Ruchirawat, Somsak
, p. 9440 - 9448 (2007/10/03)
(Chemical Equation Presented) Twenty-eight natural and unnatural lamellarins with either a saturated or an unsaturated D-ring were synthesized according to our developed synthetic route. The key step involved the Michael addition/ring closure (Mi-RC) of the benzyldihydroisoquinoline and α-nitrocinnamate derivatives, which provided the 2-carboethoxypyrrole intermediates in moderate to good yields (up to 78% yield). Subsequent hydrogenolysis/lactonization furnished lamellarins with a saturated D-ring in excellent yields (up to 93% yield). DDQ oxidation of the saturated lamellarin acetates led directly to the corresponding unsaturated analogues in 54-95% yield. In addition, only two steps in our developed strategy require column chromatography.
Studies Directed Towards Total Syntheses of the Tropoloisoquinoline Alkaloids Grandirubrine and Imerubrine. I. Preparation of Two 4,5,6-Trimethoxycyclopentisoquinolin-7-ones and Their Response to Robinson Annulation Conditions
Banwell, Martin G.,Bonadio, Anna,Turner, Kathleen A.,Ireland, Neil K.,Mackay, Maureen F.
, p. 325 - 351 (2007/10/02)
In connection with efforts to develop total syntheses of the tropoloisoquinoline alkaloids grandirubrine (1) and imerubrine (2), preparations of tricyclic ketone (8) and the related ethoxycarbonyl system (47) are described.Of the various approaches to (8)
