7547-97-9Relevant academic research and scientific papers
A relay catalysis strategy for enantioselective nickel-catalyzed migratory hydroarylation forming chiral α-aryl alkylboronates
Chen, Jian,Liang, Yong,Ma, Jiawei,Meng, Lingpu,Zhang, Yao,Zhu, Shaolin
supporting information, p. 3171 - 3188 (2021/11/16)
Ligand-controlled reactivity plays an important role in transition-metal catalysis, enabling a vast number of efficient transformations to be discovered and developed. However, a single ligand is generally used to promote all steps of the catalytic cycle (e.g., oxidative addition, reductive elimination), a requirement that makes ligand design challenging and limits its generality, especially in relay asymmetric transformations. We hypothesized that multiple ligands with a metal center might be used to sequentially promote multiple catalytic steps, thereby combining complementary catalytic reactivities through a simple combination of simple ligands. With this relay catalysis strategy (L/L?), we report here the first highly regio- and enantioselective remote hydroarylation process. By synergistic combination of a known chain-walking ligand and a simple asymmetric cross-coupling ligand with the nickel catalyst, enantioenriched α-aryl alkylboronates could be rapidly obtained as versatile synthetic intermediates through this formal asymmetric remote C(sp3)-H arylation process.
Enantioselective Total Synthesis of the Putative Biosynthetic Intermediate Ambruticin J
Trentadue, Kathryn,Chang, Chia-Fu,Nalin, Ansel,Taylor, Richard E.
supporting information, p. 11126 - 11131 (2021/06/01)
The family of anti-fungal natural products known as the ambruticins are structurally distinguished by a pair of pyran rings adorning a divinylcyclopropane core. Previous characterization of their biosynthesis, including the expression of a genetically modified producing organism, revealed that the polyketide synthase pathway proceeds via a diol intermediate, known as ambruticin J. Herein, we report the first enantioselective total synthesis of the putative PKS product, ambruticin J, according to a triply convergent synthetic route featuring a Suzuki-Miyaura cross-coupling and a Julia-Kocienski olefination for fragment assembly. This synthesis takes advantage of synthetic methodology previously developed by our laboratory for the stereoselective generation of the trisubstituted cyclopropyl linchpin.
Indirect Tertiary Alcohol Enantiocontrol by Acylative Organocatalytic Kinetic Resolution
Amalian, Jean-Arthur,Bressy, Cyril,Charles, Laurence,Desrues, Titouan,Liu, Xueyang,Monnier, Valérie,Pons, Jean-Marc,Quintard, Adrien
supporting information, p. 4332 - 4336 (2021/06/27)
The stereocontrol of tertiary alcohols represents a recurrent challenge in organic synthesis. In the present paper, we describe a simple, efficient, and indirect method to enantioselectively prepare tertiary alcohols through a chiral isothiourea catalyzed
Synthesis of α-Borylated Ketones by Regioselective Wacker Oxidation of Alkenylboronates
Corless, Victoria B.,Holownia, Aleksandra,Foy, Hayden,Mendoza-Sanchez, Rodrigo,Adachi, Shinya,Dudding, Travis,Yudin, Andrei K.
supporting information, p. 5300 - 5303 (2018/09/12)
As part of a program aimed at metal-catalyzed oxidative transformations of molecules with carbon-metalloid bonds, the synthesis of α-borylated ketones is reported via regioselective TBHP-mediated Wacker-type oxidation of N-methyliminodiacetic acid (MIDA)-protected alkenylboronates. The observed regioselectivity correlates with the hemilabile nature of the B-N dative bond in the MIDA boronate functional group, which allows boron to guide selectivity through a neighboring group effect.
Synthesis of enantiopure cyclic amino acid derivatives via a sequential diastereoselective Petasis reaction/ring closing olefin metathesis process
Morozova, Veronika A.,Beletskaya, Irina P.,Titanyuk, Igor D.
, p. 349 - 354 (2017/02/18)
A novel approach to the synthesis of enantiopure cyclic amino esters is reported. The utilization of allylboronic acid together with (S)-α-methylbenzylamine as a chiral auxiliary in the Petasis/Mannich reaction led to the formation of allylglycine derivatives in good yield and with high diastereoselectivity. Subsequent esterification, N-allylation followed by ring-closing metathesis (RCM) reaction enabled the preparation of enantiomerically pure cyclic α-amino acid derivatives.
Enantioselective syn and anti homocrotylation of aldehydes: Application to the formal synthesis of spongidepsin
Lin, Hongkun,Tian, Leiming,Krauss, Isaac J.
supporting information, p. 13176 - 13182 (2015/10/28)
Whereas crotylboration has been a useful method for synthesis of stereochemically complex products, we have shown that homocrotylboration can be achieved with cyclopropanated crotylation reagents, and that the stereoselectivity of the reaction can be predicted by analogous models. This paper presents a full account of this work, including the first examples of asymmetric anti homocrotylation. The scope of this reaction is demonstrated with highly enantioselective homocrotylation of both aliphatic and aromatic aldehydes, as well as double diastereoselection studies. An application of the synthesis of the marine natural product spongidepsin is presented, as well as streamlined syntheses of homocrotylation reagents.
Copper-Catalyzed Oxy-Alkenylation of Homoallylic Alcohols to Generate Functional syn-1,3-Diol Derivatives
Holt, Dean,Gaunt, Matthew J.
supporting information, p. 7857 - 7861 (2015/06/30)
A novel method for the synthesis of a wide range of functionalized 1,3-diol derivatives is reported. Employing a copper-catalyzed oxy-alkenylation strategy, a range of readily available, substituted homoallylic alcohol derivatives and alkenyl(aryl) iodonium salts combine to form syn-1,3-carbonates in excellent yield and with high selectivity. Furthermore, the products formed are amenable to an iterative reaction sequence, thus affording highly complex polyketide-like fragments. Polyols: The reported copper-catalyzed oxy-alkenylation strategy works well for a range of readily available, substituted homoallylic alcohol derivatives and alkenyl(aryl) iodonium salts to form syn-1,3-carbonates in excellent yield and high selectivity. Furthermore, the products formed are amenable to an iterative reaction sequence, thus affording highly complex polyketide-like fragments.
Construction of multiple, contiguous quaternary stereocenters in acyclic molecules by lithiation-borylation
Watson, Charlotte G.,Balanta, Angelica,Elford, Tim G.,Essafi, Stphanie,Harvey, Jeremy N.,Aggarwal, Varinder K.
supporting information, p. 17370 - 17373 (2015/02/05)
Lithiation of carbamates followed by borylation provides a powerful method for the homologation of boron reagents. However, when applied to hindered systems (secondary carbamates with tBu-boronic esters) for the construction of two quaternary centers, thi
SYNTHESIS OF BORONIC ESTERS AND BORONIC ACIDS USING GRIGNARD REAGENTS
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Paragraph 0114; 0118, (2013/03/26)
Boronic esters and boronic acids are synthesized at ambient temperature in an ethereal solvent by the reaction of Grignard reagents with a boron-containing substrate. The boron-containing substrate may be a boronic ester such as pinacolborane, neopentylglycolborane, or a dialkylaminoborane compound such as diisopropylaminoborane. The Grignard reagents may be preformed or generated from an alkyl, alkenyl, aryl, arylalkyl, heteroaryl, vinyl, or allyl halide compound and Mg°. When the boron-containing substrate is a boronic ester, the reactions generally proceed at room temperature without added base in about 1 to 3 hours to form a boronic ester compound. When the boron-containing substrate is a dialkylaminoborane compound, the reactions generally proceed to completion at 0°C in about 1 hour to form a boronic acid compound.
Enantioselective homocrotylboration of aliphatic aldehydes
Lin, Hongkun,Pei, Wenbo,Wang, Hao,Houk, Kendall N.,Krauss, Isaac J.
supporting information, p. 82 - 85 (2013/02/25)
A practical route to optically pure syn-homocrotylation reagents is described, including highly diastereo- and enantioselective preparation of numerous syn-homocrotyl products, as well as several matched mismatched pairs. NMR experiments suggest that the active homocrotylating species is a cyclopropylcarbinyldichloroborane generated by chloride exchange from the PhBCl2 activator. Computational studies support the intermediacy of chloroboranes and suggest that homoallyl/homocrotyl transfers occur through Zimmerman-Traxler transition states.
