468-53-1Relevant academic research and scientific papers
Palladium-catalyzed asymmetric direct intermolecular allylation of α-aryl cyclic vinylogous esters: Divergent synthesis of (+)-oxomaritidine and (?)-mesembrine
Wang, Wei,Dai, Jun,Yang, Qiqiong,Deng, Yu-Hua,Peng, Fangzhi,Shao, Zhihui
, p. 920 - 924 (2021/02/16)
We demonstrate that α-aryl cyclic vinylogous esters are competent substrates in the direct intermolecular Pd-catalyzed asymmetric allylic alkylation, enabling a straightforward enantioselective synthesis of 6-allyl-6-aryl-3-ethoxycyclohex-2-en-1-ones, common motifs embedded in numerous structurally diverse natural products. As an initial demonstration of the utility of this protocol, the first catalytic enantioselective total synthesis of (+)-oxomaritidine and an improved five-step catalytic enantioselective synthesis of (?)-mesembrine have been completed divergently.
Diversity-Oriented Approach Toward the Syntheses of Amaryllidaceae Alkaloids via a Common Chiral Synthon
Verma, Prachi,Chandra, Atish,Pandey, Ganesh
, p. 9968 - 9977 (2018/07/25)
Functionalized hydroindole (1), a common chiral synthon, for versatile transformations to synthesize a broad range of Amaryllidaceae alkaloids (AAs) including (-)-crinine, (-)-crinane, (-)-amabiline, (+)-mesembrine, (-)-maritidine, (-)-oxomaritidine, and
Asymmetric Synthesis of Remote Quaternary Centers by Copper-Catalyzed Desymmetrization: An Enantioselective Total Synthesis of (+)-Mesembrine
Bokka, Apparao,Mao, James X.,Hartung, John,Martinez, Steven R.,Simanis, Justin A.,Nam, Kwangho,Jeon, Junha,Shen, Xiaoqiang
supporting information, p. 5158 - 5162 (2018/09/13)
Catalytic asymmetric syntheses of remote quaternary stereocenters have been developed by copper-catalyzed 1,4-hydrosilylation of ?,?-disubstituted cyclohexadienones. A variety of cyclohexenones have been synthesized in good yield and excellent enantioselectivity. Versatile 2-silyloxy diene intermediates bearing ?,?-disubstituted all carbon stereogenic centers can be isolated from the mild reaction conditions. The utility of this strategy is exemplified in a catalytic asymmetric total synthesis of (+)-mesembrine.
Total Synthesis of (+)-Mesembrine Applying Asymmetric Gold Catalysis
Spittler, Michael,Lutsenko, Kiril,Czekelius, Constantin
, p. 6100 - 6105 (2016/07/26)
The total synthesis of enantiomerically pure (+)-mesembrine is described. The central pyrrolidine moiety incorporating a quaternary, all-carbon-substituted stereocenter was constructed employing an asymmetric gold-catalyzed cycloisomerization of a 1,4-diynamide.
A Concise Total Synthesis of (-)-Mesembrine
Wang, Lu-Ning,Cui, Qi,Yu, Zhi-Xiang
, p. 10165 - 10171 (2016/11/17)
A concise total synthesis of mesembrine (four steps from known compound) was achieved both racemically and asymmetrically. Two key reactions were used here. One is the Rh(I)-catalyzed [5 + 1] cycloaddition of vinylcyclopropane 3c and CO. The other one is Buchwald's Pd-catalyzed coupling reaction that coupled β,γ-cyclohexenone 2c with aryl bromide 5 (using dppe ligand for racemic or (S)-Antphos ligand for asymmetric synthesis) to give γ,γ-disubstituted α,β-cyclohexenone 1c. Finally, aza-Michael addition converted 1c to mesembrine.
Asymmetric Michael Addition Reaction of α-Aryl-Substituted Lactams Catalyzed by Chiral Quaternary Ammonium Salts Derived from Cinchona Alkaloids: A New Short Synthesis of (+)-Mesembrine
Nunokawa, Shiori,Minamisawa, Masamitsu,Nakano, Keiji,Ichikawa, Yoshiyasu,Kotsuki, Hiyoshizo
, p. 2301 - 2305 (2015/09/28)
The enantioselective Michael addition reaction of α-aryl-substituted lactams with electron-deficient olefins was efficiently catalyzed using chiral quaternary ammonium salts derived from cinchona alkaloids. This method was highly useful for the construction of an all-carbon-substituted quaternary carbon stereogenic center at the α-position of lactams in good to high yields and with good enantiomeric excess and could be applied to the short synthesis of (+)-mesembrine.
Highly chemoselective aerobic oxidation of amino alcohols into amino carbonyl compounds
Sasano, Yusuke,Nagasawa, Shota,Yamazaki, Mai,Shibuya, Masatoshi,Park, Jaiwook,Iwabuchi, Yoshiharu
supporting information, p. 3236 - 3240 (2014/04/03)
The direct oxidation of unprotected amino alcohols to their corresponding amino carbonyl compounds has often posed serious challenges in organic synthesis and has constrained chemists to adopting an indirect route, such as a protection/deprotection strategy, to attain their goal. Described herein is a highly chemoselective aerobic oxidation of unprotected amino alcohols to their amino carbonyl compounds in which 2-azaadamantane N-oxyl (AZADO)/copper catalysis is used. The catalytic system developed leads to the alcohol-selective oxidation of various unprotected amino alcohols, carrying a primary, secondary, or tertiary amino group, in good to high yield at ambient temperature with exposure to air, thus offering flexibility in the synthesis of nitrogen-containing compounds. Strong as an ox: The highly chemoselective aerobic oxidation of unprotected amino alcohols to their corresponding amino carbonyl compounds has been achieved by using 2-azaadamantane N-oxyl (AZADO)/copper catalysis. This catalytic system oxidizes not only alcohols with tertiary amino groups but also those with secondary and primary amines in good to high yield at ambient temperature in air. bpy=2,2-bipyridyl, DMAP=4-(N,N-dimethylamino)pyridine.
Double reduction of cyclic aromatic sulfonamides: Synthesis of (+)-mesembrine and (+)-mesembranol
Geoghegan, Kimberly,Evans, Paul
, p. 3410 - 3415 (2013/06/26)
The synthesis of (+)-mesembrine (1) and (+)-mesembranol (2) has been achieved from the monoterpene (S)-(-)-perillyl alcohol. Key transformations include a diastereo- and regioselective Pd-mediated intramolecular Heck reaction, and a double reduction of the resultant cyclic sulfonamide, to afford the cis-3a-aryloctahydroindole skeleton.
Consecutive sigmatropic rearrangements in the enantioselective total synthesis of (-)-joubertinamine and (-)-mesembrine
Ilardi, Elizabeth A.,Isaacman, Michael J.,Qin, Ying-chuan,Shelly, Sommer A.,Zakarian, Armen
experimental part, p. 3261 - 3269 (2009/08/15)
Joubertinamine and mesembrine are two related alkaloids isolated from Sceletium plants. From the perspective of chemical synthesis, the major challenge posed by joubertinamine and mesembrine is undoubtedly the construction of the benzylic quaternary stere
The enantioselective Birch-Cope sequence for the synthesis of carbocyclic quaternary stereocenters. Application to the synthesis of (+)-mesembrine
Paul, Tapas,Malachowski, William P.,Lee, Jisun
, p. 4007 - 4010 (2007/10/03)
A synthetic technique for generating carbocyclic quaternary stereocenters with exceptionally high levels of enantioselectivity is described. A sequence of three reactions, enantioselective Birch reduction-allylation, enol ether hydrolysis, and Cope rearrangement, is used to stereoselectively generate chiral quaternary centers on a 2-cyclohexen-1-one ring. The products of the sequence are 4,4-disubstituted-2-carboxamide-2-cyclohexen-1-one structures which are versatile intermediates in complex natural product synthesis. An application of the sequence to the synthesis of (+)-mesembrine illustrates the utility of these intermediates.
