2-Hydroxyammonium salts

Method C (catalysed by chiral ji-hydroxyammonium salts) The chiral ammonium salt (0.6 mmol) and the aldehyde (1 mmol) in the appropriate solvent (2 ml) are stirred at room temperature for 20 min. The dialkylzinc (IM in n-C6H14,2.2 ml) is added dropwise, and the mixture is stirred at room temperature for 3-6 days. The chiral alcohol is isolated using the procedure described in 12.3.1.A,... 

P-Hydroxyammonium salts can react under the strongly basic reaction conditions present in many phase-transfer reactions and the newly formed products could, in principle, serve either as effective or ineffective catalysts (Scheme 10.1) [9c]. The development of a new class of chiral phase-transfer catalysts, the W-alkyl-O-alkyl cinchona quats (Bactjve in Scheme 10.1 and 30 in Scheme 10.2), resulted from detailed mechanistic studies of these systems [5p,12], These catalysts are formed by in situ deprotonation of 28 to the alkoxide 29 followed by alkylation to form the active catalyst 30. Such catalysts offer an important second site of variation (R-, in 30) for catalyst development, which has been rapidly utilized for the preparation of more effective catalysts. 

N-condensed 31, 270 Hydroxyamines s. Aminoalcohols 2-Hydroxyammonium salts, quaternary... 

Quaternary 2-hydroxyammonium salts from oxido compds. via 1,2-iodohydrins... 

Stereospecific formatiQn of oxido compounds from quaternary hydroxyammonium salts... 

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