Crown ethers as phase-transfer catalysts. A comparison of anionic activation in aqueous–organic two-phase systems and in low polarity anhydrous solutions by perhydrodibenzo-18-crown-6, lipophilic quaternary salts, and cryptands

1980 ◽  
pp. 46-51 ◽  
Author(s):  
Dario Landini ◽  
Angelamaria Maia ◽  
Fernando Montanari ◽  
Filippo M. Pirisi
Keyword(s):  
Crown Ethers ◽  
Phase Transfer ◽  
Two Phase ◽  
Phase Transfer Catalysts ◽  
Quaternary Salts ◽  
Phase Systems

ChemInform Abstract: Catalytic and Enantiodivergent Activity of Carbohydrate Phase-Transfer Catalysts in the Reduction of Acetophenone with NaBH4 in Two-Phase Systems.

ChemInform ◽  
2010 ◽  
Vol 25 (22) ◽  
pp. no-no
Author(s):  
YU. A. ZHDANOV ◽  
YU. E. ALEKSEEV ◽  
E. L. KOROL' ◽  
T. P. SUDAREVA ◽  
V. G. ALEKSEEVA
Keyword(s):  
Phase Transfer ◽  
Two Phase ◽  
Phase Transfer Catalysts ◽  
Phase Systems

Synthese primärer und sekundärer Phosphane durch selektive Alkylierung von PH3 unter Phasentransferbedingungen / Synthesis of Primary and Secondary Phosphines by Selective Alkylation of PH3 under Phase Transfer Conditions

1990 ◽  
Vol 45 (2) ◽  
pp. 203-211 ◽  
Author(s):  
Klaus P. Langhans ◽  
Othmar Stelzer ◽  
Jürgen Svara ◽  
Norbert Weferling
Keyword(s):  
Phase Transfer ◽  
Alkyl Halides ◽  
Cyclization Reaction ◽  
High Yield ◽  
Two Phase ◽  
Phase Transfer Catalysts ◽  
Phase Systems ◽  
Selective Alkylation ◽  
Secondary Phosphines

Primary phosphines, RPH2, may be synthesized selectively by alkylation of phosphine, PH3, with alkyl halides RX (R = Me, Et, n-Bu, 2-Bu, C16H33, CH2=CH–CH2, Ph–CH2, 2-Py–CH2–CH2; X = Cl, Br) and concentrated aqueous KOH as auxilliary base in dimethylsulfoxide as a solvent or in two phase systems employing phase transfer catalysts. Under more rigorous conditions secondary phosphines R2PH (R = Me, n-Bu, CH2=CH–CH2) are also accessible in good yields. Using 1,3-dibromo(chloro)-propane or -butane diprimary phosphines H2P–(CH2)2–CHR–PH2 (R = H, Me) are obtained, while 1,4-dibromopentane in a high yield cyclization reaction leads to 2-methylphospholane (12) with a chiral C-atom in a-position.

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