- Palladium-Catalyzed Aminomethylation of Nitrodienes and Dienones via Double C—N Bond Activation
-
A new strategy for the generation of the active Pd-alkyl species from aminal via C—N bond activation has been established, in which the formation of zwitterionic intermediate through aza-Michael addition of aminal to nitrodienes or dienones is identified as a key step for the activation of the C—N bond. The efficient strategy has enabled a new palladium-catalyzed α-aminomethylation of nitrodienes and dienones via double C—N bond activation. The scope and versatility of the reaction were demonstrated and a broad range of substrates bearing electron-donating and -withdrawing groups on the aromatic rings were all compatible with this reaction to furnish the desired α-aminomethylated products in moderate to good yields with excellent regioselectivities and E/Z selectivities.
- Yu, Bangkui,Gao, Bao,Zhang, Xuexia,Zhang, Haocheng,Huang, Hanmin
-
supporting information
p. 566 - 570
(2021/02/01)
-
- Relay Catalysis to Synthesize β-Substituted Enones: Organocatalytic Substitution of Vinylogous Esters and Amides with Organoboronates
-
Organocatalysis was shown to facilitate conjugate additions to vinylogous esters and amides for the first time. Subsequent elimination of a β-alcohol or amine provided π-conjugated β-substituted enones. Remarkably, nucleophile addition to the electron-rich vinylogous substrates is more rapid than classical enones, forming monosubstituted products. A doubly organocatalytic (organic diol and methyl aniline) conjugate addition synthesized the products directly from alkynyl ketones. Both of these catalytic transformations are orthogonal to transition metal catalysis, allowing for good yields, easily accessible or commercially available reagents, high selectivity, reagent recovery and recyclability, facile scalability, and exceptional functional group tolerance.
- Sundstrom, Sasha,Nguyen, Thien S.,May, Jeremy A.
-
p. 1355 - 1359
(2020/02/13)
-
- Palladium-Catalyzed Oxidative Allylation of Sulfoxonium Ylides: Regioselective Synthesis of Conjugated Dienones
-
The first examples of palladium-catalyzed allylic C-H oxidative allylation of sulfoxonium ylides to afford the corresponding conjugated dienones with moderate to good yields have been established. The features of this novel conversion include mild reaction conditions, wide substrate scope, and excellent regioselectivity.
- Li, Chunsheng,Li, Meng,Zhong, Wentao,Jin, Yangbin,Li, Jianxiao,Wu, Wanqing,Jiang, Huanfeng
-
supporting information
p. 872 - 875
(2019/05/16)
-
- Highly regioselective introduction of aryl substituents via asymmetric 1,4-addition of boronic acids to linear α,β,γ,δ-unsaturated ketones
-
An efficient palladium(II)-catalyzed regioselective asymmetric 1,4-conjugate addition of arylboronic acids to linear α,β,γ,δ-unsaturated ketones is developed using phosphapalladacycle catalysts. The relevant 1,4-products were obtained exclusively with per
- Gan, Kennard,Ng, Jia Sheng,Sadeer, Abdul,Pullarkat, Sumod A.
-
supporting information
p. 254 - 258
(2016/01/20)
-
- D-A-π-D Synthetic approach for thienyl chalcones - NLO - a structure activity study
-
With the growing interest for organic molecules in Nonlinear Optical (NLO) applications, we have synthesized nine novel thienyl chalcones based on the D-A-π-D design. In order to establish the identity, these have been characterized in detail. Having followed the design based synthetic route, we have focused on two prime criteria for comparison; namely second harmonic generation (SHG) and non-linear absorption. In this work the role of the electron withdrawing groups, electron donating groups and extended conjugation, have been extensively studied vis-à-vis the NLO properties. The change in these properties by virtue of the molecular structure has been elucidated in this work as the structure activity relationship. Optical nonlinearity is studied using ultrafast (100 fs) laser pulses at 800 nm, employing the open aperture Z-scan technique. The compounds exhibit large effective three-photon absorption (3PA) coefficients, in the order of 10-28 m3/W2. These observations show that these compounds possess potential for application in all-optical limiting and switching devices.
- Tejkiran,Brahma Teja,Sai Siva Kumar,Sankar, Pranitha,Philip, Reji,Naveen,Lokanath,Nageswara Rao
-
-
- Asymmetric 1,4-Conjugate Addition of Diarylphosphines to α,β,γ,δ-Unsaturated Ketones Catalyzed by Transition-Metal Pincer Complexes
-
An enantioselective asymmetric 1,4-addition of diarylphosphines to linear α,β,γ,δ-unsaturated dienones was developed. A series of chiral PCP- and PCN-transition-metal (Pd, Pt and Ni) pincers, themselves prepared catalytically via asymmetric hydrophosphination, were sequentially screened to reveal the roles of backbone architecture and metal ion in catalyst design. The selected ester-functionalized PCP-palladium pincer afforded the chiral 1,4-phosphine adducts in excellent yields with up to >99% ee. The same catalyst when utilized for the hydrophosphination of an α,β,γ,δ-unsaturated malonate ester also revealed the critical role played by the ester functionality on the ligand backbone in dictating the enantioselectivity of the 1,6-adduct.
- Yang, Xiang-Yuan,Tay, Wee Shan,Li, Yongxin,Pullarkat, Sumod A.,Leung, Pak-Hing
-
supporting information
p. 5196 - 5201
(2015/11/09)
-
- Chemoselective biohydrogenation of α,β- and α,β,γ,δ-unsaturated ketones by the marine-derived fungus Penicillium citrinum CBMAI 1186 in a biphasic system
-
To broaden the range of applicability of a reduction reaction mediated by the marine fungal strain Penicillium citrinum CBMAI 1186 to organic chemical processes, the ability of whole mycelia to grow in biphasic mixtures with organic solvents was tested with acetone, ethyl acetate, n-butanol, dichloromethane, n-hexane and toluene. n-Hexane was the least toxic solvent according to the amount of mycelial mass grown in an artificial sea water medium mixed with each solvent. Therefore, whole hyphae of P. citrinum CBMAI 1186 were used as biocatalysts in the chemoselective biotransformation of the carbon-carbon double bond in α,β-, di-α,β-, and mono-α,β,γ,δ-unsaturated ketones (3a, 3c-f) in a biphasic system of phosphate buffer and n-hexane (9:1). Only the di-α,β,γ,δ-unsaturated ketone (3b) was not biocatalyzed under these conditions. In general, there were good conversions of saturated ketones by the enoate reductase enzymes of P. citrinum CBMAI 1186.
- Ferreira, Irlon M.,Meira, Eloá B.,Rosset, Isac G.,Porto, André L.M.
-
-
- NHC-catalyzed annulation of enals to 2,4-dien-1-ones: Efficient diastereoselective synthesis of 1,3-diaryl-4-styrenyl cyclopentenes
-
Nucleophilic heterocyclic carbene (NHC)-catalyzed annulation strategy has been utilized for the efficient synthesis of styrenyl-substituted cyclopentenes from 2,4-dienones. Georg Thieme Verlag Stuttgart New York.
- Sinu,Padmaja,Jini,Lakshmi, K.C. Seetha,Nair
-
supporting information
p. 1671 - 1674
(2013/09/02)
-
- Copper-catalyzed asymmetric 1,4-conjugate addition of Grignard reagents to linear α,β,γ,δ-unsaturated ketones
-
A highly regioselective and enantioselective copper-catalyzed 1,4-conjugate addition of Grignard reagents to linear α,β,γ,δ- unsaturated ketones was developed. The 1,4-addition products were obtained regioselectively in high yields with up to 98% ee. The Royal Society of Chemistry 2013.
- Ma, Zhenni,Xie, Fang,Yu, Han,Zhang, Yiren,Wu, Xiaoting,Zhang, Wanbin
-
supporting information
p. 5292 - 5294
(2013/06/27)
-
- Synthesis of substituted fluorenes by cascade allenylation, electrocyclization and intramolecular friedel-crafts reaction of 1,3-diene-substituted propargylic alcohols
-
A concise, one-step synthesis of substituted fluorenes through TiCl 4-promoted cascade allenylation, electrocyclization and intramolecular Friedel-Crafts reaction of 1,3-diene-substituted propargylic alcohols has been developed. An interesting substituent-dependent regioselectivity was observed.
- Xu, Xiangsheng,Li, Tao,Li, Xiaoqing,Shao, Jiangbin
-
p. 383 - 388
(2013/04/23)
-