2016年6月22日水曜日

A Career in Catalysis: Masakatsu Shibasaki - ACS Catalysis (ACS Publications)

A Career in Catalysis: Masakatsu Shibasaki

Naoya Kumagai^*^†, Motomu Kanai^*^‡, and Hiroaki Sasai^*^§

^† Institute
of Microbial Chemistry (BIKAKEN), Tokyo, 3-14-23 Kamiosaki, Shinagawa-ku, Tokyo 141-0021, Japan

^‡ Graduate
School of Pharmaceutical Sciences, The University
of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan

^§ The
Institute of Scientific and Industrial Research (ISIR), Osaka University, 8-1 Mihogaoka, Ibaraki-shi, Osaka 567-0047, Japan

ACS Catal., 2016, 6, pp 4699–4709

DOI: 10.1021/acscatal.6b01227

Publication Date (Web): June 20, 2016

*E-mail: nkumagai@bikaken.or.jp., *E-mail: kanai@mol.f.u-tokyo.ac.jp., *E-mail: sasai@sanken.osaka-u.ac.jp.

Abstract

Professor
Masakatsu Shibasaki’s distinguished scientific accomplishments in the
field of asymmetric catalysis are compiled here with particular emphasis
on multimetallic cooperative catalysis. In 1992, he discovered
revolutionary multimetallic chiral complexes composed of a rare earth
metal, alkaline metals, and 1,1′-binaphthyl-2-binaphthols (BINOLs) that
promoted a number of enantioselective reactions in a highly efficient
and stereoselective manner. This finding resulted in chiral
multimetallic catalysts that have significantly advanced the field of
enantioselective catalysis.

Ligand-Enabled, Copper-Catalyzed Regio- and Stereoselective Synthesis of Trialkylsubstituted Alkenylboronates from Unactivated Internal Alkynes - Journal of the American Chemical Society (ACS Publications)

Ligand-Enabled, Copper-Catalyzed Regio- and Stereoselective Synthesis of Trialkylsubstituted Alkenylboronates from Unactivated Internal Alkynes - Journal of the American Chemical Society (ACS Publications)

Taisuke Itoh^†, Yohei Shimizu^†, and Motomu Kanai^*^†^‡

^† Graduate
School of Pharmaceutical Sciences, The University
of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan

^‡ Kanai
Life Science Catalysis Project, ERATO, Japan
Science Technology Agency, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan

J. Am. Chem. Soc., 2016, 138 (24), pp 7528–7531

DOI: 10.1021/jacs.6b04646

Publication Date (Web): June 07, 2016

*kanai@mol.f.u-tokyo.ac.jp

Abstract

We
report the first copper-catalyzed regio- and stereoselective
borylalkylation of dialkylsubstituted internal alkynes with
bis(pinacolato)diboron and alkyl halides. A catalytically generated
borylcopper species containing a novel π-accepting N-heterocyclic
carbene ligand chemoselectively reacted with unactivated internal
alkynes over alkyl halides. The intermediate alkenylcopper species
subsequently reacted with alkyl halides, affording the desired products.
The copper catalyst differentiated steric demands between the two
aliphatic substituents on the C≡C triple bond of the alkyne substrates
to exhibit high regioselectivity from a wide range of alkyne/alkyl
halide combinations. This method is useful for the straightforward
synthesis of trialkylsubstituted alkenylboronates, i.e., versatile
precursors for tetrasubstituted alkenes containing three or four
different alkylsubstituents, which are difficult to synthesize by other
methods.

Nickel-Catalyzed Asymmetric Kumada Cross-Coupling of Symmetric Cyclic Sulfates - Journal of the American Chemical Society (ACS Publications)

Meredith S. Eno, Alexander Lu, and James P. Morken^*

Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States

J. Am. Chem. Soc., Article ASAP

DOI: 10.1021/jacs.6b03384

Publication Date (Web): June 08, 2016

*morken@bc.edu

Abstract

Nickel-catalyzed
enantioselective cross-couplings between symmetric cyclic sulfates and
aromatic Grignard reagents are described. These reactions are effective
with a broad range of substituted cyclic sulfates and deliver products
with asymmetric tertiary carbon centers. Mechanistic experiments point
to a stereoinvertive S_N2-like oxidative addition of a nickel complex to the electrophilic substrate.

Selective Catalytic Oxidation of Unprotected Carbohydrates - ACS Catalysis (ACS Publications)

Kevin Chung and Robert M. Waymouth^*

Department of Chemistry, Stanford University, Stanford, 94305 California, United States

ACS Catal., 2016, 6, pp 4653–4659

DOI: 10.1021/acscatal.6b01501

Publication Date (Web): June 06, 2016

*E-mail: waymouth@stanford.edu.

Abstract

The
development of new strategies for the direct catalytic
functionalization of unprotected carbohydrates would be an enabling
advance for glycoscience. Herein we report that the catalytic oxidation
of unprotected carbohydrates can be carried out selectively with
[(neocuproine)Pd(OAc)]₂(OTf)₂ (1) to
generate the 3-ketoses. Catalytic aerobic oxidation can be carried out
with Pd loadings as low as 1% in the presence of phenolic additives.
Catalytic oxidation of a variety of unprotected pyranosides in
acetonitrile or acetonitrile/water with Pd catalyst 1 with either
oxygen or benzoquinone selectively generates the 3-ketoses. Minor
amounts of the 4-ketoses are formed competitively, particularly in the
case of pyranosides bearing axial substituents at C4 of the pyranoside.
Catalytic oxidations can also be carried out in trifluorethanol, but for
pyranosides bearing axial substituents at C2 or C4, selective oxidation
to the 3-ketose is accompanied by epimerization to afford the
equatorial 3-ketoses. Catalytic oxidation of unprotected hexafuranosides
or sialic acid derivatives occurs selectively at the exocyclic diol or
triol in trifluoroethanol to generate exocyclic hydroxyketones.

Palladium-Catalyzed Regioselective C–H Bond Arylations of Benzoxazoles and Benzothiazoles at the C7 Position - ACS Catalysis (ACS Publications)

Fatma Abdellaoui^†^‡, Chiraz Youssef^‡, Hamed Ben Ammar^‡, Thierry Roisnel^†, Jean-François Soulé^*^†, and Henri Doucet^*^†

^† Institut des Sciences
Chimiques de Rennes, UMR 6226 CNRS-Université de Rennes “Organométalliques:
Matériaux et Catalyse”, Campus de Beaulieu, 35042 Rennes, France

^‡ Laboratoire de
Synthèse Organique Asymétrique et Catalyse Homogène,
(UR 11ES56) Université de Monastir, Faculté des Sciences
de Monastir, Avenue de l’environnement, Monastir 5000, Tunisia

ACS Catal., 2016, 6, pp 4248–4252

DOI: 10.1021/acscatal.6b00678

Publication Date (Web): May 31, 2016

*E-mail: jean-francois.soule@univ-rennes1.fr., *E-mail: henri.doucet@univ-rennes1.fr.

Abstract

We
report herein, a very simple catalytic system for the direct arylation
of benzoxazole and benzothiazole derivatives at C7 position, namely,
phosphine-free PdCl₂ associated with PivOK in NMP at 150 °C.
(Thio)phenoxy chelation-assisted Pd-catalyzed C–H bond cleavage, from an
opened intermediate, was proposed to explain this unique
regioselectivity. This reaction allows the synthesis of
2-amino-6-arylphenols through the ring opening of the benzoxazole.

2,5-Oxyarylation of Furans: Synthesis of Spiroacetals via Palladium-Catalyzed Aerobic Oxidative Coupling of Boronic Acids with α-Hydroxyalkylfurans - Organic Letters (ACS Publications)

Jiuyi Li, Hui Peng, Furong Wang, Xiujun Wang, Huanfeng Jiang, and Biaolin Yin^*

School of Chemistry and Chemical
Engineering, South China University of Technology, Guangzhou 510641, China

Org. Lett., Article ASAP

DOI: 10.1021/acs.orglett.6b01472

Publication Date (Web): June 16, 2016

*E-mail: blyin@scut.edu.cn.

Abstract

A
protocol for the 2,5-oxyarylation of furan rings via Pd-catalyzed
aerobic oxidative coupling of boronic acids with α-hydroxyalkylfurans is
reported. This protocol provides rapid, green access to diverse
biologically interesting and synthetically useful unsaturated
spiroacetals from sustainable furan derivatives.

Ruthenium-Catalyzed Dehydrogenative β-Benzylation of 1,2,3,4-Tetrahydroquinolines with Aryl Aldehydes: Access to Functionalized Quinolines - Organic Letters (ACS Publications)

Zhenda Tan, Huanfeng Jiang, and Min Zhang^*

School of Chemistry &
Chemical Engineering, South China University
of Technology, Wushan
Road - 381, Guangzhou 510641, People’s Republic of China

Org. Lett., Article ASAP

DOI: 10.1021/acs.orglett.6b01390

Publication Date (Web): June 14, 2016

*minzhang@scut.edu.cn

Abstract

A
new benzylation protocol, enabling straightforward access to
β-benzylated quinolines, has been demonstrated. By employing readily
available [RuCl₂(p-cymene)]₂ as a catalyst and O₂
as a sole green oxidant, various 1,2,3,4-tetrahydroquinolines were
efficiently converted in combination with aryl aldehydes into desired
products in a step- and atom-economic fashion together with the
advantages of excellent functional group tolerance and chemoselectivity,
offering an important basis for the transformation of saturated N-heterocycles into functionalized N-heteroaromatics
via a dehydrogenative cross-coupling strategy. Mechanistic
investigations support that the reaction undergoes a
monodehydrogenation-triggered β-benzylation mode.

2016年6月21日火曜日

Highly mono-selective ortho-trifluoromethylation of benzamides via 8-aminoquinoline assisted Cu-promoted C–H activations - Chemical Communications (RSC Publishing)

Liang Hu,^a^b Xiang Chen,^a Qingwen Gui,^a Ze Tan*^a and Gangguo Zhu^b

Show Affiliations

Chem. Commun., 2016,52, 6845-6848

DOI: 10.1039/C6CC02412B
Received 19 Mar 2016, Accepted 23 Apr 2016
First published online 26 Apr 2016

A highly mono-selective ortho-trifluoromethylation of benzamides was achieved via Cu-promoted C–H activations. The reaction employs an 8-aminoquinoline group as the bidentate directing group and Togni reagent II as the CF₃ source. The reaction tolerated a wide variety of functional groups and various ortho-trifluoromethylated benzamides were efficiently synthesized in 36–82% yield.

Graphical abstract: Highly mono-selective ortho-trifluoromethylation of benzamides via 8-aminoquinoline assisted Cu-promoted C–H activations

Oxygen insertion into boroles as a route to 1,2-oxaborines - Chemical Communications (RSC Publishing)

Sam Yruegas,^a Dayna C. Patterson^a and Caleb D. Martin*^a

Show Affiliations

Chem. Commun., 2016,52, 6658-6661

DOI: 10.1039/C6CC02040B

Received 07 Mar 2016,
Accepted 26 Mar 2016
First published online 29 Mar 2016

The synthesis of 1,2-oxaborines is accomplished via the reaction of pentaarylboroles with N-methylmorpholine-N-oxide via
a 1,1-insertion reaction. The aromatic nature of 1,2-oxaborines was
evaluated by computing nuclear independent chemical shift (NICS) values.
Collectively, the experimental and computational studies indicate the
unsaturated central BOC₄ ring has appreciable aromatic character.

Graphical abstract: Oxygen insertion into boroles as a route to 1,2-oxaborines

The first synthesis and X-ray crystallographic analysis of an oxygen-bridged planarized triphenylborane - Chemical Communications (RSC Publishing)

The first synthesis and X-ray crystallographic analysis of an oxygen-bridged planarized triphenylborane - Chemical Communications (RSC Publishing)

Yuichi Kitamoto,*a Takatsugu Suzuki,b Yasuo Miyata,b Hiroshi Kita,c Kenji Funakid and Shuichi Oi*a
Show Affiliations
Chem. Commun., 2016,52, 7098-7101
DOI: 10.1039/C6CC02440H
Received 21 Mar 2016, Accepted 29 Apr 2016
First published online 29 Apr 2016

An oxygen-bridged
planarized triphenylborane has been successfully synthesized. X-ray
crystallographic analysis revealed that the molecule has a complete
planarized structure and the shortest C–B bonds among the triarylboranes
synthesized to date.

Graphical abstract: The first synthesis and X-ray crystallographic analysis of an oxygen-bridged planarized triphenylborane

Radical C–H arylations of (hetero)arenes catalysed by gallic acid - Chemical Communications (RSC Publishing)

Radical C–H arylations of (hetero)arenes catalysed by gallic acid - Chemical Communications (RSC Publishing)
Marcelle D. Perretti,^a Diego M. Monzón,^a Fernando P. Crisóstomo,^a Víctor S. Martín^a and Romen Carrillo*^a

Show Affiliations

Chem. Commun., 2016, Advance Article

DOI:10.1039/C5CC09911K

Received 01 Dec 2015,
Accepted 15 Jan 2016
First published online 15 Jan 2016

Gallic acid efficientlycatalyses radical arylations in water–acetone at room temperature. This
methodology proved to be versatile and scalable. Therefore, it constitutes a greener alternative to arylation. Moreover, considering that gallic acid is an abundant vegetable tannin, this work also
unleashes an alternative method for the reutilisation of bio-wastes.

Graphical abstract: Radical C–H arylations of (hetero)arenes catalysed by gallic acid

An effective host material with thermally activated delayed fluorescence formed by confined conjugation for red phosphorescent organic light-emitting diodes - Chemical Communications (RSC Publishing)

Xiang-Yang Liu,^a Feng Liang,^a Yi Yuan,^a Lin-Song Cui,^a Zuo-Quan Jiang*^a and Liang-Sheng Liao*^a

Show Affiliations

Chem. Commun., 2016, Advance Article

DOI: 10.1039/C6CC02856J
Received 06 Apr 2016, Accepted 24 May 2016
First published online 08 Jun 2016 A thermally activated delayed fluorescence material 2,6-bis(9,9-diphenylacridin-10(9H)-yl)pyrazine
was designed and synthesized. The twisted configuration made it
possesses very small singlet–triplet splitting. A red electroluminescent
device based on this new host material is able to achieve ∼26% external
quantum efficiency and relatively flat efficiency roll-off.

Graphical abstract: An effective host material with thermally activated delayed fluorescence formed by confined conjugation for red phosphorescent organic light-emitting diodes

Quinonediimines as redox-active organocatalysts for oxidative coupling of aryl- and alkenylmagnesium compounds under molecular oxygen - Chemical Communications (RSC Publishing)

Toru Amaya,*^a Riyo Suzuki^a and Toshikazu Hirao*^a

Show Affiliations

Chem. Commun., 2016,52, 7790-7793

DOI: 10.1039/C6CC03053J
Received 12 Apr 2016, Accepted 26 Apr 2016
First published online 12 May 2016

It is revealed that N,N′-diphenyl-p-benzoquinonediimine
works as a redox-active organocatalyst for the oxidative homo-coupling
of aryl- and alkenylmagnesium compounds under molecular oxygen. The
catalytic cycle was formally monitored by ¹H NMR experiments.

Graphical abstract: Quinonediimines as redox-active organocatalysts for oxidative coupling of aryl- and alkenylmagnesium compounds under molecular oxygen

2016年6月15日水曜日

Meta-Selective CAr–H Nitration of Arenes through a Ru3(CO)12-Catalyzed Ortho-Metalation Strategy - Journal of the American Chemical Society (ACS Publications)

Zhoulong Fan^†^‡, Jiabin Ni^†^‡, and Ao Zhang^*^†^‡

^† CAS Key Laboratory of Receptor Research, and Synthetic Organic &
Medicinal Chemistry Laboratory (SOMCL), Shanghai Institute of Materia
Medica (SIMM), Chinese Academy of Sciences, Shanghai 201203, China

^‡ University of Chinese Academy of Sciences, Beijing 100049, China

J. Am. Chem. Soc., Article ASAP

DOI: 10.1021/jacs.6b03402

Publication Date (Web): May 15, 2016

*aozhang@simm.ac.cn

Abstract

The first example of transition metal-catalyzed meta-selective C_Ar–H nitration of arenes is described. With the use of Ru₃(CO)₁₂ as the catalyst and Cu(NO₃)₂·3H₂O as the nitro source, a wide spectrum of arenes bearing diversified N-heterocycles
or oximido as the directing groups were nitrated with meta-selectivity
exclusively. Mechanism studies have demonstrated the formation of a new
18e-octahedral ruthenium species as a key ortho-C_Ar–H metalated intermediate, which may be responsible for the subsequent meta-selective electrophilic aromatic substitution (S_EAr).
Moreover, this approach provides a fast-track strategy for atom/step
economical synthesis of many useful pharmaceutical molecules.

登録: 投稿 (Atom)