39770-04-2Relevant articles and documents
General approach to the synthesis of the chlorosulfolipids danicalipin A, mytilipin A, and malhamensilipin A in enantioenriched form
Chung, Won-Jin,Carlson, Joseph S.,Vanderwal, Christopher D.
, p. 2226 - 2241 (2014)
A second-generation synthesis of three structurally related chlorosulfolipids has been developed. Key advances include highly stereocontrolled additions to α,β-dichloroaldehydes, kinetic resolutions of complex chlorinated vinyl epoxide intermediates, and Z-selective alkene cross metatheses of cis-vinyl epoxides. This strategy facilitated the synthesis of enantioenriched danicalipin A, mytilipin A, and malhamensilipin A in nine, eight, and 11 steps, respectively.
A synthesis of the chlorosulfolipid mytilipina a via a longest linear sequence of seven steps
Chung, Won-Jin,Carlson, Joseph S.,Bedke, D. Karl,Vanderwal, Christopher D.
, p. 10052 - 10055 (2013)
Magnificent seven: The chlorosulfolipid mytilipin A was synthesized in racemic form in seven steps and in enantioenriched form in eight steps. Key transformations include a highly diastereoselective bromoallylation of a sensitive α,β-dichloroaldehyde, a kinetic resolution of a vinyl epoxide, a convergent and highly Z-selective alkene cross-metathesis, and a chemoselective and diastereoselective dichlorination of a complex diene.
Acridine Photocatalysis: Insights into the Mechanism and Development of a Dual-Catalytic Direct Decarboxylative Conjugate Addition
Arman, Hadi D.,Dang, Hang T.,Haug, Graham C.,Larionov, Oleg V.,Nguyen, Viet D.,Nguyen, Vu T.,Vuong, Ngan T. H.
, p. 11448 - 11457 (2020/11/17)
Conjugate addition is one of the most synthetically useful carbon-carbon bond-forming reactions; however, reactive carbon nucleophiles are typically required to effect the addition. Radical conjugate addition provides an avenue for replacing reactive nucleophiles with convenient radical precursors. Carboxylic acids can serve as simple and stable radical precursors by way of decarboxylation, but activation to reactive esters is typically necessary to facilitate the challenging decarboxylation. Here, we report a direct, dual-catalytic decarboxylative radical conjugate addition of a wide range of carboxylic acids that does not require acid preactivation and is enabled by the visible light-driven acridine photocatalysis interfaced with an efficient copper catalytic cycle. Mechanistic and computational studies provide insights into the roles of the ligands and metal species in the dual-catalytic process and the photocatalytic activity of substituted acridines.
Cerium(IV) Carboxylate Photocatalyst for Catalytic Radical Formation from Carboxylic Acids: Decarboxylative Oxygenation of Aliphatic Carboxylic Acids and Lactonization of Aromatic Carboxylic Acids
Hirosawa, Keishi,Mashima, Kazushi,Satoh, Tetsuya,Shinohara, Koichi,Shirase, Satoru,Tamaki, Sota,Tsurugi, Hayato
supporting information, (2020/03/25)
We found that in situ generated cerium(IV) carboxylate generated by mixing the precursor Ce(OtBu)4 with the corresponding carboxylic acids served as efficient photocatalysts for the direct formation of carboxyl radicals from carboxylic acids under blue light-emitting diodes (blue LEDs) irradiation and air, resulting in catalytic decarboxylative oxygenation of aliphatic carboxylic acids to give C-O bond-forming products such as aldehydes and ketones. Control experiments revealed that hexanuclear Ce(IV) carboxylate clusters initially formed in the reaction mixture and the ligand-to-metal charge transfer nature of the Ce(IV) carboxylate clusters was responsible for the high catalytic performance to transform the carboxylate ligands to the carboxyl radical. In addition, the Ce(IV) carboxylate cluster catalyzed direct lactonization of 2-isopropylbenzoic acid to produce the corresponding peroxy lactone and ?3-lactone via intramolecular 1,5-hydrogen atom transfer (1,5-HAT).
SYNTHESIS OF STRAIGHT-CHAIN LEPIDOPTERAN PHEROMONES THROUGH ONE- OR TWO- CARBON HOMOLOGATION OF FATTY ALKENES
-
, (2020/02/14)
Methods for the preparation of alkenes including insect pheromones are described. The methods include homologation reactions employing reagents such as 1,3-diesters, epoxides, cyanoacetates, and cyanide salts for elongation of starting materials and intermediates by one or two carbon atoms. The alkenes include insect pheromones useful in a number of agricultural applications.
(Ar-tpy)RuII(ACN)3: A Water-Soluble Catalyst for Aldehyde Amidation, Olefin Oxo-Scissoring, and Alkyne Oxygenation
Joarder, Dripta De,Gayen, Subrata,Sarkar, Rajarshi,Bhattacharya, Rajarshi,Roy, Sima,Maiti, Dilip K.
, p. 8468 - 8480 (2019/07/03)
The synthetic chemists always look for developing new catalysts, sustainable catalysis, and their applications in various organic transformations. Herein, we report a new class of water-soluble complexes, (Ar-tpy)RuII(ACN)3, utilizing designed terpyridines possessing electron-donating and -withdrawing aromatic residues for tuning the catalytic activity of the Ru(II) complex. These complexes displayed excellent catalytic activity for several oxidative organic transformations including late-stage C-H functionalization of aldehydes with NH2OR to valuable primary amides in nonconventional aqueous media with excellent yield. Its diverse catalytic power was established for direct oxo-scissoring of a wide range of alkenes to furnish aldehydes and/or ketones in high yield using a low catalyst loading in the water. Its smart catalytic activity under mild conditions was validated for dioxygenation of alkynes to highly demanding labile synthons, 1,2-diketones, and/or acids. This general and sustainable catalysis was successfully employed on sugar-based substrates to obtain the chiral amides, aldehydes, and labile 1,2-diketones. The catalyst is recovered and reused with a moderate turnover. The proposed mechanistic pathway is supported by isolation of the intermediates and their characterization. This multifaceted sustainable catalysis is a unique tool, especially for late-stage functionalization, to furnish the targeted compounds through frequently used amidation and oxygenation processes in the academia and industry.
Fluorinated Musk Fragrances: The CF2Group as a Conformational Bias Influencing the Odour of Civetone and (R)-Muscone
Callejo, Ricardo,Corr, Michael J.,Yang, Mingyan,Wang, Mingan,Cordes, David B.,Slawin, Alexandra M. Z.,O'Hagan, David
, p. 8137 - 8151 (2016/06/13)
The difluoromethylene (CF2) group has a strong tendency to adopt corner over edge locations in aliphatic macrocycles. In this study, the CF2group has been introduced into musk relevant macrocyclic ketones. Nine civetone and five muscone analogues have been prepared by synthesis for structure and odour comparisons. X-ray studies indeed show that the CF2groups influence ring structure and they give some insight into the preferred ring conformations, triggering a musk odour as determined in a professional perfumery environment. The historical conformational model of Bersuker and co-workers for musk fragrance generally holds, and structures that become distorted from this consensus, by the particular placement of the CF2groups, lose their musk fragrance and become less pleasant.
Biological Investigations of (+)-Danicalipin A Enabled Through Synthesis
Bailey, Adrian M.,Wolfrum, Susanne,Carreira, Erick M.
supporting information, p. 639 - 643 (2016/02/27)
A total synthesis of the chlorosulfolipid (+)-danicalipin A has been accomplished in 12 steps and 4.4 % overall yield. The efficient and scalable synthesis enabled in-depth investigations of the lipid's biological properties, in particular cytotoxicity towards various mammalian cell lines. Furthermore, the ability of (+)-danicalipin A to increase the uptake of fluorophores into bacteria and mammalian cells was demonstrated, indicating it may enhance membrane permeability. By comparing (+)-danicalipin A with racemic 1,14-docosane disulfate, and the diol precursor of (+)-danicalipin A, we have shown that both chlorine and sulfate functionalities are necessary for biological activity.
The difluoromethylene (CF2) group in aliphatic chains: Synthesis and conformational preference of palmitic acids and nonadecane containing CF2 groups
Wang, Yi,Callejo, Ricardo,Slawin, Alexandra M.Z.,O'Hagan, David
supporting information, p. 18 - 25 (2014/01/23)
The syntheses of palmitic acids and a nonadecane are reported with CF 2 groups located 1,3 or 1,4 to each other along the aliphatic chain. Specifically 8,8,10,10- and 8,8,11,11-tetrafluorohexadecanoic acids (6b and 6c) are prepared as well as the singly modified analogue 8,8-difluorohexadecanoic acid (6a). Also 8,8,11,11-tetrafluorononadecane (27) is prepared as a pure hydrocarbon containing a 1,4-di-CF2 motif. The modified palmitic acids are characterized by differential scanning calorimetry (DSC) to determine melting points and phase behaviour relative to palmitic acid (62.5 °C). It emerges that 6c, with the CF2 groups placed 1,4- to each other, has a significantly higher melting point (89.9 °C) when compared to the other analogues and palmitic acid itself. It is a crystalline compound and the structure reveals an extended anti-zig-zag chain. Similarly 8,8,11,11- tetrafluorononadecane (27) adopts an extended anti-zig-zag structure. This is rationalized by dipolar relaxation between the two CF2 groups placed 1,4 to each other in the extended anti-zig-zag chain and suggests a design modification for long chain aliphatics which can introduce conformational stability.
A relay ring-opening/double ring-closing metathesis strategy for the bicyclic macrolide-butenolide core structures
Halle, Mahesh B.,Fernandes, Rodney A.
, p. 63342 - 63348 (2015/02/19)
A concise strategy has been developed for the synthesis of the bicyclic macrolide-butenolide core structures of various natural products with the macrolide ring size ranging from 12- to 16-membered. The bicyclic structure was easily assembled using the relay ring-opening/double ring-closing metathesis strategy. An efficient synthesis of (±)-desmethyl manshurolide has been achieved as an application of this strategy. This journal is
