Asymmetric phase-transfer alkylation catalyzed by a chiral quaternary phosphonium salt with a multiple hydrogen-bonding site

1998 ◽  
Vol 39 (32) ◽  
pp. 5807-5810 ◽  
Author(s):  
Kei Manabe
Keyword(s):  
Hydrogen Bonding ◽  
Phosphonium Salt ◽  
Phase Transfer ◽  
Multiple Hydrogen Bonding ◽  
Quaternary Phosphonium Salt ◽  
Hydrogen Bonding Site ◽  
Bonding Site

scholarly journals Taming the Reactivity of Alkyl Azides by Intramolecular Hydrogen Bonding: Site-Selective Conjugation of Unhindered Diazides

2021 ◽  
Author(s):  
Koshiro Maegawa ◽  
Hiroki Tanimoto ◽  
Seiji Onishi ◽  
Takenori Tomohiro ◽  
Tsumoru Morimoto ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Click Chemistry ◽  
Intramolecular Hydrogen Bonding ◽  
Alkyl Azides ◽  
Organic Azides ◽  
Intramolecular Hydrogen ◽  
Site Selective ◽  
Hydrogen Bonding Site ◽  
Bonding Site

Organic azides are still in the center of click chemistry connecting two molecules. However, taming the conjugation selectivity of azides is difficult without the help of the bulky groups. We...

Dipeptide-Based Phosphonium Salt Catalysis: Application to Enantioselective Synthesis of Fused Tri- and Tetrasubstituted Aziridines

Synlett ◽  
2019 ◽  
Vol 30 (19) ◽  
pp. 2101-2106 ◽  
Author(s):  
Jia-Hong Wu ◽  
Jianke Pan ◽  
Tianli Wang
Keyword(s):  
Phosphonium Salt ◽  
Phase Transfer ◽  
Asymmetric Reactions ◽  
Phosphonium Salts ◽  
Catalytic Systems ◽  
The Past ◽  
Versatile Tool ◽  
Quaternary Phosphonium Salt ◽  
Near Future ◽  
New Phase

Over the past decades, phase-transfer catalysis (PTC), generally based on numerous chiral quaternary ammonium salts, has been recognized as a powerful and versatile tool for organic synthesis in both industry and academia. In sharp contrast, PTC involving chiral phosphonium salts as the catalysts is insufficiently developed. Recently, our group realized the first enantioselective aza-Darzens reaction for preparing tri- and tetrasubstituted aziridine derivatives under bifunctional phosphonium salt catalysis. This article briefly discusses the recent development in asymmetric reactions (mainly including nucleophilic additions and cyclizations) promoted by chiral quaternary phosphonium salt catalysts. We expect that more catalytic asymmetric reactions will be developed on the basis of such new phase-transfer catalytic systems in the near future.

SOD activities of the copper complexes with tripodal polypyridylamine ligands having a hydrogen bonding site

2001 ◽  
Vol 324 (1-2) ◽  
pp. 108-116 ◽  
Author(s):  
Koichiro Jitsukawa ◽  
Manabu Harata ◽  
Hidekazu Arii ◽  
Hiromu Sakurai ◽  
Hideki Masuda
Keyword(s):  
Hydrogen Bonding ◽  
Copper Complexes ◽  
Hydrogen Bonding Site ◽  
Bonding Site

Photochemical Deracemization of Chiral Sulfoxides Catalyzed by a Hydrogen-Bonding Xanthone Sensitizer

Synthesis ◽  
2019 ◽  
Vol 51 (23) ◽  
pp. 4417-4416 ◽  
Author(s):  
Laura Wimberger ◽  
Thilo Kratz ◽  
Thorsten Bach
Keyword(s):  
Hydrogen Bonding ◽  
Sulfur Atom ◽  
Acetonitrile Solution ◽  
Photochemical Behavior ◽  
Chiral Sulfoxides ◽  
Hydrogen Bonding Site ◽  
Bonding Site

Several chiral sulfoxides with a lactam hydrogen-bonding site were prepared and their photochemical behavior was studied in the presence of xanthone and thioxanthone sensitizers. While acyclic sulfoxides showed only decomposition, chiral benzothiazinone-1-oxides with a stereogenic sulfur atom underwent a stereomutation upon irradiation at λ = 366 nm in the presence of catalytic quantities of a xanthone sensitizer. A chiral xanthone with a 1,5,7-trimethyl-3-azabicyclo-[3.3.1]nonan-2-one backbone was employed in catalytic quantities (5 mol%) to achieve a deracemization reaction of racemic benzothiazinone-1-oxides in acetonitrile solution. Five substrates could be successfully deracemized in good yields and with up to 55% ee.

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