73818-55-0Relevant articles and documents
Heavier Carbonyl Olefination: The Sila-Wittig Reaction
Reiter, Dominik,Frisch, Philipp,Szilvási, Tibor,Inoue, Shigeyoshi
, p. 16991 - 16996 (2019/10/16)
The Wittig reaction is one of the most versatile tools in the repertoire of organic chemists. Thus, a broad variety of carbonyl compounds can be converted to tailor-made alkenes with phosphorus ylides under mild conditions. However, no comparable reaction has been reported for silanones, the silicon congeners of ketones. Here, we demonstrate for the first time the successful application of the Wittig olefination to iminosilylsilanone 1. The selective formation of a series of silenes (R2Sia? CR2) via the sila-Wittig reaction revealed an unprecedented approach to otherwise elusive compounds. In addition, the highly reactive and zwitterionic nature of 1 was also susceptible to nucleophilic attacks and cycloaddition reactions by and with the phosphorus ylides. Our results therefore make another important contribution to discovering the differences and similarities between carbon and silicon.
Catalyst-Enabled Site-Divergent Stereoselective Michael Reactions: Overriding Intrinsic Reactivity of Enynyl Carbonyl Acceptors
Uraguchi, Daisuke,Shibazaki, Ryo,Tanaka, Naoya,Yamada, Kohei,Yoshioka, Ken,Ooi, Takashi
supporting information, p. 4732 - 4736 (2018/04/23)
A site-divergent stereoselective Michael reaction system is developed based on the identification of two distinct catalysts. Cinchonidine-derived thiourea catalyzes the 1,4-addition of prochiral azlactone enolates to enynyl N-acyl pyrazoles in a highly diastereo- and enantioselective manner to give stereochemically defined alkynes, while P-spiro chiral triaminoiminophosphorane catalytically controls the stereoselective 1,6-addition and the consecutive γ-protonation of the vinylogous enolate intermediate to afford Z,E-configured conjugated dienes. This 1,6-adduct serves as a valuable precursor for the synthesis of a 2-amino-2-deoxy sugar.
New reactions and reactive intermediates in the pyrolysis of cyclic phosphonium ylides
Aitken, R. Alan,Bj?rnstad, Vidar,Massil, Tracy,Skramstad, Jan,Young, Robert J.
, p. 293 - 301 (2017/10/27)
Pyrolysis, either neat or in diphenyl ether solution, results in the conversion of both 4-triphenylphosphoranylidenetetrahydrofuran-2,3,5-trione and 4-triphenylphosphoranylidenetetrahydrothio-phene-2,3,5-trione into 3,5-bis(triphenylphosphoranylidene)cyclopentane-1,2,4-trione. These reactions involve extrusion of CO2 or COS to give 3-triphenylphosphoranylidenecyclopropane-1,2-dione which further loses CO to give triphenylphosphoranylideneketene. The precise way in which these two reactive phosphorus compounds combine to give the observed product has been examined by chemical and isotopic labelling studies. Cyclotrimerization of triphenylphosphoranylideneketene upon thermolysis in diphenyl ether has also been observed for the first time. The erroneous literature interpretation of the 13C NMR spectrum for triphenylphosphoranylideneketene is corrected.
A cell-permeable and triazole-forming fluorescent probe for glycoconjugate imaging in live cells
Shie, Jiun-Jie,Liu, Ying-Chih,Hsiao, Jye-Chian,Fang, Jim-Min,Wong, Chi-Huey
supporting information, p. 1490 - 1493 (2017/02/05)
A new fluorescence-forming probe, coumOCT, designed by fusing cyclooctyne with a coumarin fluorophore was successfully used for the imaging of azido-glycoconjugates in living HeLa cells. This probe is cell-permeable and generates fluorescence after triazole formation, thus minimizing the background signal and enabling the real-time intracellular imaging of glycoconjugate trafficking.
Ravynic acid, an antibiotic polyeneyne tetramic acid from: Penicillium sp. elucidated through synthesis
Myrtle,Beekman,Barrow
, p. 8253 - 8260 (2016/09/09)
A new antibiotic natural product, ravynic acid, has been isolated from a Penicillium sp. of fungus, collected from Ravensbourne National Park. The 3-acylpolyenyne tetramic acid structure was definitively elucidated via synthesis. Highlights of the synthetic method include the heat induced formation of the 3-acylphosphorane tetramic acid and a selective Wittig cross-coupling to efficiently prepare the natural compounds carbon skeleton. The natural compound was shown to inhibit the growth of Staphylococcus aureus down to concentrations of 2.5 g mL-1.
REACTIVE LABELLING COMPOUNDS AND USES THEREOF
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, (2015/11/16)
Provided are azido-BODIPY compounds of formula (I), cyclooctyne-based fluorogenic probes of formula (IV), and activity-based probes of formula (VI). These compounds undergo azide alkyne cycloadditions (AAC) with to form triazolyl products. The provided compounds are useful for detection and imaging of alkyne-, or azide-containing molecules. Methods for detection and imaging biomolecules using compounds of the present disclosure are disclosed.
REACTIVE LABELLING COMPOUNDS AND USES THEREOF
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Paragraph 00206; 00207, (2015/12/08)
Provided are azido-BODIPY compounds of formula (I), cyclooctyne-based fluorogenic probes of formula (IV), and activity-based probes of formula (VI). These compounds undergo azide-alkyne cycloadditions (AAC) with to form triazolyl products. The provided compounds are useful for detection and imaging of alkyne-, or azide-containing molecules. Methods for detection and imaging biomolecules using compounds of the present disclosure are disclosed.
Semisynthesis of (+)-angeloyl-gutierrezianolic acid methyl ester diterpenoid
Marcos,Benéitez,Moro,Basabe,Díez,Urones
experimental part, p. 8605 - 8614 (2011/01/04)
This paper describes the use of zamoranic acid in the first semisynthesis of the furolabdane (+)-angeloyl-gutierrezianolic acid methyl ester diterpenoid, which also establishes the absolute configuration of the natural product. Direct deconjugation of Δs
Toward the development of a general chiral auxiliary. Enantioselective alkylation and a new catalytic asymmetric addition of silyloxyfurans: Application to a total synthesis of (-)-rasfonin
Boeckman Jr., Robert K.,Pero, Joseph E.,Boehmler, Debra J.
, p. 11032 - 11033 (2007/10/03)
An enantioselective total synthesis of the apoptosis-inducing natural product, (-)-rasfonin, is described. Camphor lactam-mediated asymmetric alkylation reactions enabled the installation of three stereogenic centers with >95:5 diastereoselectivity. A modified Corey-Peterson olefination was employed in the construction of the (E,E)-diene system. A highly diastereoselective, asymmetric vinylogous Mukaiyama aldol addition was conducted using a chiral cationic oxazaborolidine catalyst. The pyranone core of the natural product was prepared via a DBU-promoted rearrangement of a furanol to its corresponding pyranol with concomitant [1,4]-silyl transfer. Copyright
