− 4 −CSJ Journal Selects Vol. 2

Asymmetric Catalysis

Use of In Situ Generated Nitrosocarbonyl Compounds in Catalytic Asymmetric α-Hydroxylation and α-Amination Reactions

Biplab Maji* and Hisashi Yamamoto*Bull. Chem. Soc. Jpn. 2015, 88, 753-762

doi:10.1246/bcsj.20150040

H. Yamamoto

MnO2

PG

HN

OH*

Mg-cat.

R1

O

R2XR

O

R1

O

XR

O

ONHBoc

Cu-cat.X = O, SR

2

R1

OP(OEt)2

O

R1

R2

OP(OEt)2

NHPG

OO

*

R2 Cu-cat.

R1

O

R2

O

OR

R1

O

R2

O

ORN OHPG

*

secondaryamine-cat.

OR R

OHN

OHPG

Asymmetric hydroxylation Asymmetric amination

nitrosocarbonylcompounds

PGN

O

*

Accounts for C-X Bond Formation Nitrosocarbonyl as Electrophilic N/O Source; Cu, Mg Catalysts

Chiral Ammonium Hypoiodite-catalyzed Enantioselective Oxidative Dearomatization of 1-Naphthols Using Hydrogen Peroxide

Muhammet Uyanik, Niiha Sasakura, Erina Kaneko, Kento Ohori, and Kazuaki Ishihara*Chem. Lett. 2015, 44, 179-181

doi:10.1246/cl.141012

K. IshiharaOH

OH

OO

OO

chiral precatalyst30% H2O2

Toluene/H2O, 20 °C

N+

I–Ar

Ar

R Rhigh yield, high ee

Ar = 3,5-[3,5-(CF3)2C6H3]2C6H3

Editor's Choice Oxidative Dearomatization; Chiral Hypoiodite

1,4-Addition Reaction of 5H-Oxazol-4-ones to Allenic Esters and Ketones Catalyzed by Chiral Guanidines

Nari Jin, Tomonori Misaki,* andTakashi Sugimura*Chem. Lett. 2013, 42, 894-896

doi:10.1246/cl.130295

T. Misaki

ON

O

R1

+

1a(5 mol%)

N

N

NH OH

F3C CF3

CF3

CF3

ON

OR1

R2

O

chiral γ -butenolide

1a

R2

O

Cl Clup to 98 % ee

Me

MeR2 = OPh or alkyl

OMe

O

OO

R1

(R2 = OPh)

OH

O

OO

(+)-crobarbatic acid

2

3 4

6

4

8

Editor's Choice Enantioselective 1,4-Addition; Organocatalysts

Enantioselective Synthesis Induced by the Helical Molecular Arrangement in the Chiral Crystal of Achiral Tris(2-hydroxyethyl) 1,3,5-Benzenetricarboxylate in Conjunction with Asymmetric Autocatalysis

Tsuneomi Kawasaki,* Mizuki Uchida,Yoshiyasu Kaimori, Taisuke Sasagawa,Arimasa Matsumoto, and Kenso Soai*Chem. Lett. 2013, 42, 711-713

doi:10.1246/cl.130185

K. Soai

Left−handed M−crystal

CD(–)224KBr

N

NR2

OHS

CO2R1

R1O2C CO2R1

R1 = −CH2CH2OH

Right−handed P−crystal

CD(+)224KBr N

NR2 CHO + i −Pr2Zn

AsymmetricAutocatalysis

N

NR2

OHR

AsymmetricAutocatalysis

R2 = t−Bu−C≡C−

> 99.5% ee

> 99.5% ee

Editor's Choice Asymmetric Autocatalysis; Chiral Crystals

− 5 − CSJ Journal Selects Vol. 2

Preparation of Diastereomerically Pure and Mixed (S)-PhGly/BIPHEP/Ru(II) Complexes and Their Catalytic Behavior with Li2CO3 in Asymmetric Cyanosilylation of Benzaldehyde

Nobuhito Kurono, Taiki Katayama, and Takeshi Ohkuma*Bull. Chem. Soc. Jpn. 2013, 86, 577-582

doi:10.1246/bcsj.20120351

T. Ohkuma

Selected Paper Asymmetric Cyanosilylation; Ru(II)/BIPHEP Complexes

Asymmetric Synthesis of 1,3-Oxazolidines via Intramolecular Aza-Michael Addition by Bifunctional Organocatalysts

Yukihiro Fukata, Keisuke Asano,* and Seijiro Matsubara*Chem. Lett. 2013, 42, 355-357

doi:10.1246/cl.121245

K. Asano

up to 87% ee(after recrystallization: 98% ee)

R

OO

N

toluene, 0 °C, 24 h

Ts R'

N

NH

NS NH

H

H

CF3 CF3R

OOH

R' H

N

+Ts

Letter Organocatalysts; 1,3-Oxazolidines

Extraordinary Microwave Effect on atropo-Enantioselective Catalytic Reduction of Biaryl Lactones

Kazuya Nushiro, Satoshi Kikuchi, andTohru Yamada*Chem. Lett. 2013, 42, 165-167

doi:10.1246/cl.2013.165

T. Yamada

O

CH3

O

OH3C

CH3

O

CH3

OHM MP

H3CH3C

NB

O

H PhPh

CH3

10 mol%

in THF 30 °C

Microwave2.45 GHz

Microwaveenhancement

Dynamic Kinetic Resolution

Reaction Acceleration

BH3•THF

86% yield, 92% eeConventional:

Microwave:82% yield, 91% ee

/ 4320 min

/ 20 minKeeping high enantioselectivity!!

OH

Editor's Choice Microwave Effect; Catalytic atropo-Enantioselective Reduction