Dialkylamino alcohols

The p-substituted amino ketones can be reduced readily to the more stable P-dialkylamino alcohols, many of which are useful local anaesthetics. Thus the local anaesthetic Tutocaine is made from the Mannich base derived from formaldehyde, methyl ethyl ketone and dimethylamine, followed by reduction and conversion into the p-aminobenzoate ... 

The chiral f5-dialkylamino alcohol DAIB serves as an efficient asymmetric catalyst for the addition of organozinc reagents to aldehydes. The reaction of diethylzinc with benzaldehyde in the presence of 2 mol % of (2S)-(-)-DAIB to give (S)-1-phenyl-1-propanol in 89% ee is described in the procedure which follows. DAIB exhibits the... 

In the same way 2-47 and 3-47a dialkylamino alcohols were methylated, silylated and stannylatcd via chiral x-lithiated carbamate sparteine complexes (>95- >98% ee), as well as 1,3-propanediol and 1,4-butanediol (95 >99.5% ee)45. 

Amino Alcohol Catalyzed Alkylation. (—)-3-exo-(Dimethylamino)-isobomeol [( —)-DAIB] is a sterically restrained jS-dialkylamino alcohol that has proven to be an extremely efficient catalyst 13). For instance, in the presence of 2 mol % of (—)-DAIB, the reaction of benzaldehyde and diethylzinc proceeds smoothly to give, after aqueous workup, (5)-1 -phenyl-1 -propanol in 98% ee and in 97% yield along with a small amount of benzyl alcohol (Scheme 9). Nonpolar solvents such as toluene, hexane, ether, or their mixtures produce satisfactory results. The optical yield in toluene is affected by temperature and decreases from 98% at —20°C to less than 95% at 50°C. The catalytic enantioselective reaction has been extended to a range of alkylating agents and aldehyde substrates, which are summarized in Scheme 10 (75). p-Substituted ben-... 

Most reactions have been conducted using readily available, naturally occurring, chiral modifiers. The auxiliaries employed for the modification of LAH are classified into three types (i) alcohol modifiers (ii) dialkylamino alcohol modifiers and (iii) primary or secondary amines and amino or monoalkylamino alcohol modifiers. Most asymmetric reductions have been investigated with acetophenone (1) as the substrate. Structures (3) to (24) summarize the chiral modifiers, enantiomeric excesses ee) and absolute configurations of the 1-phenyl-1-ethanol (2) produced. 

Pracejus and coworkers reported the first Michael addition/enantioselective protonation mediated by cinchona alkaloids [15]. The authors put a special emphasis on the requirement of using chiral P-N,N-dialkylamino alcohol to achieve significant inductions. The addition of benzyl thiol 16 on 2-phthalimidoacrylate 17 catalyzed by 5 mol% of quinidine 3 gave the best selectivity (Scheme 7.10). 

Katritzky and Harris reported in 1992 the use of diethylzinc for the chiral amino alcohol-mediated enantioselective addition to the C=N bond in these compounds (Scheme 12) [34]. These substrates act as masked activated N-acylimines. Of the large variety of Hgands available for the catalytic asymmetric reactions of dialkylzinc reagents,the sterically constrained P-dialkylamino alcohol, (-)-N,N-dibutylnorephedrine (DBNE) 18, prepared by alkylation of commercially available norephedrine, was selected for this study. Some preliminary experiments conducted with the use of -(aminobenzyl)benzotriazoles gave the ethylated product, but with no enantioselectivity. Diethylzinc (Et2Zn) was found to react even in the absence of a chiral promoter. The behavior of the less reactive N-(amidobenzyl)benzotriazoles 19a-g was then investigated. 

The fl-substituted amino ketones can be reduced readily to the more stable P-dialkylamino alcohols, many of which are useful local anaesthetics. Thus the... 

Dialkylamino alcohols and their esters are useful local anesthetics. Suggest a synthesis of the anesthetic Tutocaine hydrochloride, heginning with 2-butanone and using any other organic compounds. (Hint Identify the embedded four-carbon unit of 2-butanone in the product and apply retrosynthetic disconnections from it.)... 

Kosmalski T, Wojtczak A, Zaidlewicz M. Asymmetric synthesis of -dialkylamino alcohols by transfer hydrogenation of a-dialkylamino ketones. Tetrahedron Asymm. 2009 20 (10) 1138-1143. 

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