197219-01-5Relevant articles and documents
Enantioselective Total Synthesis of (+)-Sieboldine A
Abd El-Gaber, Mohammed K.,Yasuda, Shigeo,Iida, Eisuke,Mukai, Chisato
, p. 320 - 323 (2017)
The first total synthesis of (+)-sieboldine A was completed starting from 5-(p-methoxybenzyloxy)pentyne in 19 steps. The enantioselective Keck allylation provided the dienyne derivative, which was exposed to the Pauson-Khand conditions to afford the bicyclo[4.3.0]nonenone derivative with high stereoselectivity with an ee value of 93%. The following Ueno-Stork reaction formed the cis-hydrindane core with a quaternary carbon center. The late-stage Schmidt glycosylation led to the formation of the N-hydroxyazacyclononane ring.
Total synthesis of distaminolyne A
Dumpala, Mohan,Theegala, Srinivas,Palakodety, Radha Krishna
, p. 1273 - 1275 (2017)
Herein we report the stereoselective total synthesis of first occurrence distaminolyne A via aminolytic kinetic resolution, Corey-Fuch's reaction for alkyne formation and Cardiot-Chodkiewicz cross coupling followed by Wittig olefination as the key steps.
Fluorine in pheromones: Synthesis of fluorinated 12-dodecanolides as emerald ash borer pheromone mimetics
Zhang, Qingzhi,Teschers, Charlotte S.,Callejo, Ricardo,Yang, Mingyan,Wang, Mingan,Silk, Peter J.,Ryall, Krista,Roscoe, Lucas E.,Cordes, David B.,Slawin, Alexandra M.Z.,O'Hagan, David
supporting information, p. 2917 - 2922 (2019/04/30)
A series of five 12-dodecanolides have been synthesised containing CF2 groups at C5, C6, C7, C8 and in one case, a double substitution at C5 & C8, as a strategy to bias the conformational space accessed by these macrocycles, and to assess if th
C-F bond cleavage enabled redox-neutral [4+1] annulation via C-H bond activation
Wang, Cheng-Qiang,Ye, Lu,Feng, Chao,Loh, Teck-Peng
supporting information, p. 1762 - 1765 (2017/02/15)
Using α,α-difluoromethylene alkyne as a nontraditional one-carbon reaction partner, a synthetically novel method for the construction of isoindolin-1-one derivatives via Rh(III)-catalyzed [4+1] annulation reaction is reported. The 2-fold C-F bond cleavage not only enables the generation of desired product under an overall oxidant-free condition but also results in a net migration of carbon-carbon triple bond. In addition, the present reaction protocol exhibits a tolerance of a wide spectrum of functional groups due to the mild reaction conditions employed.
Sulfated tungstate as hydroxyl group activator for preparation of benzyl, including p-methoxybenzyl ethers of alcohols and phenols
Katkar, Kamlesh V.,Veer, Sachin D.,Akamanchi, Krishnacharya G.
supporting information, p. 1893 - 1901 (2016/11/25)
Sulfated tungstate was found to be an effective heterogeneous and reusable catalyst for hydroxy group activation–mediated preparation of benzylic ethers including p-methoxybenzylic ethers of a wide range of alcohols and phenols under mild reaction conditions.
Stereochemistry and Mechanism of Undecylprodigiosin Oxidative Carbocyclization to Streptorubin B by the Rieske Oxygenase RedG
Withall, David M.,Haynes, Stuart W.,Challis, Gregory L.
supporting information, p. 7889 - 7897 (2015/07/02)
The prodiginines are a group of specialized metabolites that share a 4-methoxypyrrolyldipyrromethene core structure. Streptorubin B is a structurally remarkable member of the prodiginine group produced by Streptomyces coelicolor A3(2) and other actinobacteria. It is biosynthesized from undecylprodigiosin by an oxidative carbocyclization catalyzed by the Rieske oxygenase-like enzyme RedG. Undecylprodigiosin derives from the RedH-catalyzed condensation of 2-undecylpyrrole and 4-methoxy-2, 2′-bipyrrole-5-carboxaldehyde (MBC). To probe the mechanism of the RedG-catalyzed reaction, we synthesized 2-(5-pentoxypentyl)-pyrrole, an analogue of 2-undecylpyrrole with an oxygen atom next to the site of C-C bond formation, and fed it, along with synthetic MBC, to Streptomyces albus expressing redH and redG. This resulted in the production of the 6′-oxa analogue of undecylprodigiosin. In addition, a small amount of a derivative of this analogue lacking the n-pentyl group was produced, consistent with a RedG catalytic mechanism involving hydrogen abstraction from the alkyl chain of undecylprodigiosin prior to pyrrole functionalization. To investigate the stereochemistry of the RedG-catalyzed oxidative carbocyclization, [7′-2H](7′R)-2-undecylpyrrole and [7′-2H](7′S)-2-undecylpyrrole were synthesized and fed separately, along with MBC, to S. albus expressing redH and redG. Analysis of the extent of deuterium incorporation into the streptorubin B produced in these experiments showed that the pro-R hydrogen atom is abstracted from C-7′ of undecylprodigiosin and that the reaction proceeds with inversion of configuration at C-7′. This contrasts sharply with oxidative heterocyclization reactions catalyzed by other nonheme iron-dependent oxygenase-like enzymes, such as isopenicillin N synthase and clavaminate synthase, which proceed with retention of configuration at the carbon center undergoing functionalization. (Chemical Equation Presented).
Stereodivergent Intramolecular C(sp3)-H Functionalization of Azavinyl Carbenes: Synthesis of Saturated Heterocycles and Fused N -Heterotricycles
Lindsay, Vincent N. G.,Viart, Hélène M.-F.,Sarpong, Richmond
supporting information, p. 8368 - 8371 (2015/07/15)
A general approach for the formation of five-membered saturated heterocycles by intramolecular C(sp3)-H functionalization is reported. Using N-sulfonyltriazoles as Rh(II) azavinyl carbene equivalents, a wide variety of stereodefined cis-2,3-dis
Enynone dihydroxylation-cyclisation as a route to densely functionalised 3(2H)-furanone derivatives: An approach to the core of the zaragozic acids
Ostovar, Mehrnoosh,Marson, Charles M.
, p. 6639 - 6647 (2013/07/26)
The synthesis of an advanced intermediate is described that could secure the polyoxygenated core of zaragozic acids and related natural products. The key strategy employs a two-step synthesis of the 3(2H)-furanone ring system by catalytic dihydroxylation-
Benzylation of hydroxy groups with tertiary amine as a base
Gathirwa, Jeremiah W.,Maki, Toshihide
experimental part, p. 370 - 375 (2012/01/14)
The benzylation of hydroxy groups in the presence of tertiary amines is described. A mixture of an alcohol and a benzyl halide afforded the corresponding benzyl ether in good to excellent yields in the presence of diisopropylethylamine. The importance of solventless conditions was observed. The reaction showed high tolerance to many functional groups including benzoate, even at a reaction temperature of 150 °C. Sodium iodide was found to be an efficient catalyst to accelerate the reaction.
Studies toward the synthesis of spirolide C: Exploration into the formation of the 23-membered all-carbon macrocyclic framework
Stivala, Craig E.,Gu, Zhenhua,Smith, Lindsay L.,Zakarian, Armen
supporting information; experimental part, p. 804 - 807 (2012/05/04)
The synthesis of two complex subunits en route to spirolide C is described. A key alkyllithium addition to an aldehyde joins the fragments, which are advanced in order to investigate a ring-closing metathesis to form the 23-membered all-carbon macrocyclic
