119405-97-9Relevant articles and documents
Gold-catalyzed [4+3] and [4+4]-annulation reactions of: T -butyl propiolate derivatives with epoxides and oxetanes for the construction of 1,4-dioxepane and 1,5-dioxocane cores
Sahani, Rajkumar Lalji,Liu, Rai-Shung
, p. 7482 - 7485 (2016)
Gold-catalyzed [4+n]-annulations (n = 3, 4) of tert-butyl propiolate derivatives with epoxides or oxetanes proceed smoothly to yield seven- or eight-membered oxacyclic products efficiently. In the context of the [4+3]-annulations, product analysis reveals a retention of stereochemistry upon the intramolecular SN2 attack of an epoxide. We also report the [4+5]-annulation between one tert-butyl propiolate and γ-lactol, to manifest the utility toward medium-sized rings.
Copper(i)-catalysed stereoselective debromoborylation of aliphatic 1,1-dibromo-1-alkenes with bis(pinacolato)diboron
Pang, Yadong,Kojima, Ryoto,Ito, Hajime
, p. 6187 - 6190 (2018)
A stereoselective debromoborylation of aliphatic 1,1-dibromo-1-alkenes to prepare (Z)-1-bromo-1-alkenylboronate esters using copper(i) catalysts was developed. The debromoborylation of various aliphatic 1,1-dibromo-1-alkenes in the presence of a copper(i) catalyst and bis(pinacolato)diboron proceeded smoothly to produce (Z)-1-bromo-1-alkenylboronate esters in good yields with only Z geometry.
Regio- and diastereoselective construction of spirocyclopenteneoxindoles through phosphine-catalyzed [3 + 2] annulation of methyleneindolinone with alkynoate derivatives
Zhang, Jiayong,Cheng, Cheng,Wang, Dian,Miao, Zhiwei
, p. 10121 - 10128 (2017)
A phosphine-catalyzed [3 + 2] annulation of isatin-derived α,β-unsaturated ketones with alkynoates for the synthesis of cyclopentene spiro-oxindole skeletons has been developed. This reaction afforded the desired products in high to excellent yields (up to 99%) with high regioselectivity and moderate to high diastereoselectivities (up to 20:1). This strategy allows facile diastereoselective preparation of biologically important spiro-(cyclopentene) oxindoles containing three contiguous stereocenters, including the quaternary stereogenic center joining the two rings.
Phosphine-Catalyzed Intermolecular Dienylation of Alkynoate with para-Quinone Methides
Song, Zefeng,Wang, Weijia,Liu, Zhixin,Lu, Yue,Wang, De
, p. 8590 - 8599 (2021)
An interesting remote I-C 1,6-Addition and an isomerization cascade reaction for phosphine-catalyzed activated alkynes have been disclosed. The products featuring a functional diene and a 1,1-diaryl methyl motif have been obtained in moderate to good yields (30-86%) by applying para-quinone methides (p-QMs) and I-substituted alkynoate with tributylphosphine (PnBu3) catalysis, along with high regioselectivity and stereoselectivity (dr > 20:1). The wide scope of compatible substrates (35 examples), such as indolyl, oxindolyl, ester, and cinnamyl, expand the utility of this methodology. A plausible mechanism and some applications of it have also been presented.
Removal of triphenylphosphine oxide by precipitation with zinc chloride in polar solvents
Batesky, Donald C.,Goldfogel, Matthew J.,Weix, Daniel J.
, p. 9931 - 9936 (2017)
While the use of triphenylphosphine as a reductant is common in organic synthesis, the resulting triphenylphosphine oxide (TPPO) waste can be difficult to separate from the reaction product. While a number of strategies to precipitate TPPO are available, none have been reported to work in more polar solvents. We report here that mixing ZnCl2 with TPPO precipitates a TPPO?Zn complex in high yield in several common polar organic solvents. The solvent compatibility of this procedure and the reliability of the precipitation in the presence of polar functional groups were examined to show the utility and limitations of this method.
Nickel-Catalyzed, Regio- and Enantioselective Benzylic Alkenylation of Olefins with Alkenyl Bromide
Liu, Jiandong,Gong, Hegui,Zhu, Shaolin
supporting information, p. 4060 - 4064 (2020/12/25)
A NiH-catalyzed migratory hydroalkenylation reaction of olefins with alkenyl bromides has been developed, affording benzylic alkenylation products with high yields and excellent chemoselectivity. The mild conditions of the reaction preclude olefinic products from undergoing further isomerization or subsequent alkenylation. Catalytic enantioselective hydroalkenylation of styrenes was achieved by using a chiral bisoxazoline ligand.
Ru-Catalyzed [3 + 2] Cycloaddition of Nitrile Oxides and Electron-Rich Alkynes with Reversed Regioselectivity
Feng, Qiang,Huang, Hai,Sun, Jianwei
supporting information, p. 2431 - 2436 (2021/05/05)
Polarity reversal ("umpolung") of a functional group can override its inherent reactivity and lead to distinct bond-forming modes. Herein we describe a rarely studied cycloaddition between nitrile oxides and electron-rich alkynes with reversed regioselect
Catalytic Enantioselective Synthesis of 1,4-Keto-Alkenylboronate Esters and 1,4-Dicarbonyls
Liang, Michael Z.,Meek, Simon J.
supporting information, p. 14234 - 14239 (2019/08/30)
A catalytic enantioselective method for the synthesis of 1,4-keto-alkenylboronate esters by a rhodium-catalyzed conjugate addition pathway is disclosed. A variety of novel, bench-stable alkenyl gem-diboronate esters are synthesized. These easily accessible reagents react smoothly with a collection of cyclic α,β-unsaturated ketones, generating a new C?C bond and stereocenter. Products are isolated in up to 99 % yield with greater than 20:1 E/Z and greater than 99:1 e.r. Mechanistic studies show the site-selectivity of transmetalation and reactivity is ligand dependent. The utility of the approach is highlighted by gram-scale synthesis of enantioenriched cyclic 1,4-diketones, and stereoselective transformations of the products by hydrogenation, allylation, and isomerization.
Synthesis of 1,3-Diynes via Cadiot-Chodkiewicz Coupling of Volatile, in Situ Generated Bromoalkynes
Knutson, Phil C.,Fredericks, Haleigh E.,Ferreira, Eric M.
supporting information, p. 6845 - 6849 (2018/10/25)
A convenient Cadiot-Chodkiewicz protocol that facilitates the use of low molecular weight alkyne coupling partners is described. The method entails an in situ elimination from a dibromoolefin precursor and immediate subjection to copper-catalyzed conditions, circumventing the hazards of volatile brominated alkynes. The scope of this method is described, and the internal 1,3-diyne products are preliminarily evaluated in ruthenium-catalyzed azide-alkyne cycloadditions.
Remote sp3 C–H Amination of Alkenes with Nitroarenes
Xiao, Jichao,He, Yuli,Ye, Feng,Zhu, Shaolin
supporting information, p. 1645 - 1657 (2018/05/16)
Direct installation of a functional group at remote, unfunctionalized sites in an alkyl chain is a synthetically valuable but rarely reported process. The remote relay hydroarylamination of distal and proximal olefins, and of olefin isomeric mixtures, has been achieved through NiH-catalyzed alkene isomerization and sequential reductive hydroarylamination with nitroarenes. This provides an attractive approach to the direct installation of a distal arylamino group within alkyl chains. The single-step conversion of simple olefins and nitro(hetero)arenes to value-added arylamines is a practical strategy for amine synthesis as well as the remote activation of sp3 C–H bonds. The value of this transformation is further supported by the regioconvergent arylamination of isomeric mixtures of olefins. Modern organic synthesis requires more efficient strategies, such as C–H functionalization, with which to construct complex molecules from readily available chemicals. Undirected functionalization of remote aliphatic C–H bonds is a synthetically valuable but largely unknown process. Synergistic combination of metal-catalyzed chainwalking (migration of a double bond along the hydrocarbon chain, a process involving repeated migratory insertions and β-hydride eliminations) and cross-coupling chemistry offers a general approach to the remote functionalization of easily accessed unsaturated hydrocarbon substrates. In this paper, we demonstrate that direct installation of a distal arylamino group can be achieved from two common feedstock chemicals (olefins and nitroarenes) via nickel hydride chemistry. It is anticipated that the strategy could inspire the development of other remote functionalizations with different regioselectivity as well as asymmetric transformations. Zhu and colleagues describe the remote hydroamination of alkenes with nitro(hetero)arenes through nickel-catalyzed alkene isomerization and sequential reductive relay hydroamination process. Using two common feedstock chemicals, olefins and nitroaromatics, in an operationally simple procedure, this attractive protocol provides efficient and practical access to a wide range of arylamines under mild conditions.
