77877-57-7Relevant academic research and scientific papers
Acid-catalyzed chirality-transferring intramolecular Friedel-Crafts cyclization of α-hydroxy-α-alkenylsilanes
Sakaguchi, Kazuhiko,Kubota, Shunnichi,Akagi, Wataru,Ikeda, Naoko,Higashino, Masato,Ariyoshi, Shoma,Shinada, Tetsuro,Ohfune, Yasufumi,Nishimura, Takahiro
supporting information, p. 8635 - 8638 (2019/07/25)
Acid-catalyzed intramolecular Friedel-Crafts cyclization of optically active α-hydroxy-α-alkenylsilanes possessing a benzene ring (>99% ee) with TMSOTf as a Lewis acid gave enantio-enriched tetrahydronaphthalenes (up to 98% ee). The silyl group attached to the chiral carbon played a crucial role in the chirality transfer.
Catalytic Generation and Chemoselective Transfer of Nucleophilic Hydrides from Dihydrogen
Pape, Felix,Brechmann, Lea T.,Teichert, Johannes F.
supporting information, p. 985 - 988 (2019/01/04)
Copper(I)–N-heterocyclic-carbene (NHC) complexes enabled the catalytic generation of nucleophilic hydrides from dihydrogen (H2) and their subsequent transfer to allylic chlorides. The highly chemoselective catalyst displayed no concomitant hydrogenation reactivity; in fact, the terminal double bond formed in the hydride transfer remained intact. Switching to deuterium gas (D2) allowed for regioselective monodeuteration with excellent isotope incorporation.
Stereoselective Alkyne Hydrohalogenation by Trapping of Transfer Hydrogenation Intermediates
Das, Manas,Kaicharla, Trinadh,Teichert, Johannes F.
supporting information, p. 4926 - 4929 (2018/08/24)
A catalytically generated vinylcopper complex, the reactive intermediate of a copper(I)-catalyzed alkyne transfer hydrogenation, can be trapped by commercially available halogen electrophiles. In this manner, internal alkynes can stereoselectively be hydrohalogenated to the corresponding vinyl chlorides, bromides, and iodides.
Catalytic Anti-Markovnikov Hydroallylation of Terminal and Functionalized Internal Alkynes: Synthesis of Skipped Dienes and Trisubstituted Alkenes
Mailig, Melrose,Hazra, Avijit,Armstrong, Megan K.,Lalic, Gojko
, p. 6969 - 6977 (2017/05/31)
We have developed catalytic anti-Markovnikov hydroallylation of terminal and functionalized internal alkynes. In this article, we describe the development of the reaction, exploration of the substrate scope, and a study of the reaction mechanism. Synthesis of skipped dienes through the hydroallylation of terminal alkyl and aryl alkynes with simple allyl phosphates and 2-substituted allyl phosphates is described. The hydroallylation of functionalized internal alkynes leads to the formation of skipped dienes containing trisubstituted alkenes. We demonstrate that the hydroallylation of internal alkynes can be used in the regio- and diastereoselective synthesis of complex trisubstituted alkenes. A mechanism of the hydroallylation reaction is proposed, and experimental evidence is provided for the key steps of the catalytic cycle. Stoichiometric experiments demonstrate an unexpected role of lithium alkoxide in the carbon-carbon bond-forming step of the reaction. A study of the hydrocupration of internal alkynes provides new insight into the structure, stability, and reactivity of alkenyl copper intermediates, as well as insight into the source of the regioselectivity in reactions of internal alkynes.
Titanium-Promoted Cross-Coupling for the Selective Synthesis of Polysubstituted, Conjugated Amides
Chenniappan, Vinoth Kumar,Rahaim, Ronald J.
supporting information, p. 5090 - 5093 (2016/10/14)
α,β-Unsaturated amides are important building blocks and are key structural elements in a number of biologically active natural products. Despite their importance and prevalence, few methods exist to prepare conjugated amides directly and modularly. To address this gap, a titanium-promoted coupling of alkynes and isocyanates has been developed. The method is highly stereoselective, producing only the E isomer with good chemoselectivity and regioselectivity (>95/5), for unsymmetrical internal alkynes that contain a steric bias. The reactive titanacyclopentene intermediate formed from the coupling of the alkyne and isocyanate was additionally reacted with various electrophiles to access tetrasubstituted enamides.
Directing group-controlled hydrosilylation: Regioselective functionalization of alkyne
Kawasaki, Yuuya,Ishikawa, Youhei,Igawa, Kazunobu,Tomooka, Katsuhiko
, p. 20712 - 20715 (2012/02/15)
Pt(0)-catalyzed hydrosilylation of unsymmetric alkynes proceeds in a highly regioselective manner with a dimethylvinylsilyl (DMVS) group as the directing group. This hydrosilylation affords a single regioisomer of silylalkenes from propargylic and homopro
Stereoselective anti-SN2′ Mitsunobu reaction of α-hydroxy-α-alkenylsilanes
Higashino, Masato,Ikeda, Naoko,Shinada, Tetsuro,Sakaguchi, Kazuhiko,Ohfune, Yasufumi
supporting information; experimental part, p. 422 - 425 (2011/03/21)
A novel silyl group-directed anti-SN2′ reaction of allylic alcohols under Mitsunobu reaction conditions is described. The Mitsunobu reaction of α-hydroxy-α-alkenylsilanes with a TBS or TIPS group gave the anti-SN2′ product, in which regio- and stereochemical outcomes of the reaction depended on the steric bulkiness of the silyl group.
An atom-economic and selective ruthenium-catalyzed redox isomerization of propargylic alcohols. An efficient strategy for the synthesis of leukotrienes
Trost, Barry M.,Livingston, Robert C.
supporting information; experimental part, p. 11970 - 11978 (2009/02/05)
Catalytic ruthenium complexes in conjunction with an indium cocatalyst and Broensted acid isomerize primary and secondary propargylic alcohols in good yields to provide trans enals and enones exclusively. Readily available indenylbis(triphenylphosphine)ruthenium chloride, in the presence of indium triflate and camphorsulfonic acid, gives the best turnover numbers and reactivity with the broadest range of substrates. Deuterium labeling experiments suggest that the process occurs through propargylic hydride migration followed by protic cleavage of the resultant vinylruthenium intermediate. Application of this method to the synthesis of leukotriene B4 demonstrates its utility and extraordinary selectivity.
Asymmetric Cyclopropanation Using New Chiral Auxiliaries Derived from D-Fructose
Kang, Jahyo,Lim, Geun Jho,Yoon, Suk Kyoon,Kim, Moohi Yoo
, p. 564 - 577 (2007/10/02)
Acetals of α,β-unsaturated aldehydes with 3-O-alkylated derivatives of 1,2-O-isopropylidene-β-D-fructopyranose and 1,2-O-isopropylidene-β-D-psicopyranose, which are readily available from D-fructose, were cyclopropanated with Et2Zn and CH2I2 with good diastereoselectivity.The effects of structure of the acetals on enantioselectivity were examined.
Selenium--Stabilized Anions. Preparation of α,β-Unsaturated Carbonyl Compounds Using Propargyl Selenides. Synthesis of (+/-)-7-Hydroxymyoporone
Reich, Hans J.,Shah, Shrenik K.,Gold Paul M.,Olson Richard E.
, p. 3112 - 3120 (2007/10/02)
The reaction of alkyl halides, carbonyl compounds, and trimethylsilyl chloride with the mono- and dianion (1) prepared by deprotonation of phenyl propargyl selenide with lithium diisopropylamide gives 1- or 3-monosubstituted or 1,3-disubstituted propargyl selenides (3a).Oxidation to selenoxides (3b) results in rearrangement to 2-(phenylseleno)-1,3-disubstituted propenones.The rate of rearrangement of propargyl selenoxides increases dramatically when the phenyl group is replaced by a 2-nitrophenyl group, and an intermediate allenyl selenate ester (7c) can be observed by low-temperature NMR.By appropriate modification of oxidation conditions, modest yields of 2-iodopropenes (e.g., 10) or the selenium-free enones or enals can be obtained.A synthesis of (+/-)-7-hydroxymyoporone (15) and its epimer has been carried out by using the dianion 1 to assemble the carbon skeleton.The preparation of α-lithioallenyl phenyl selenide (26) has been accomplished, and its reaction with electrophiles has been studied.
