Sulfinyl amino alcohols

Diastereoselective allylation under aqueous Barbier conditions of a-amino aldehydes with the chiral building block (Ss)-3-chloro-2-(p-tolylsulfinyl)-l-propene to give enantiomerically pure sulfinyl amino alcohols in good yields and with high diastereoselectivity was reported (Eq. 8.34).73... 

The reaction has been extensively used for the synthesis of a-amino acids (entries 3-5),559 //-/ -amino alcohols (entry 6),560 aminophenol (entry 7),561 optically active A-substituted glycines (entries 7 and 8),562 a-hydrazinocarboxylic acids (entry 9),563 A-sulfinyl and A-alkoxy-a-amino acids (entries 10 and ll),564 and propargyl amines (entry 12).565... 

The reduction of the chiral /3-hydroxy sulfinyl imines with HBcat or LiBHEt3 provided syn- and anti- 1,3-amino alcohols, respectively, with very high diastereomeric ratios (Equations (255) and (256)).1072... 

Diastereoselective allylation of optically pure sulfinyl dienal complexes using tributyl allyltin can be obtained (Scheme 138). 2,4-Hexadien-1,6-dial iron tricarbonyl complex (88) undergoes nucleophilic addition reactions with diaUcylzincs in the presence of a catalytic amount of an optically active amino alcohol (Scheme 139). Very high enantio-and diastereoselectivity is observed. Related reactions of (88) with chiral allyl boronic esters give allylated alcohols in very high enantiomeric excess. 

It was recently shown that the addition of metal salts dramatically increased the diastereoselectivity on sulfinyl ketimine enolates, which provides a rapid route to syn- and anri-1,3-amino alcohols (Scheme 3, eq 1). For two other recent examples, a silver nitrate (AgNOsj/LDA combination has been used in the formation of selenium containing heterocycles as potential antitumor agents (Scheme 3, eq 2), while an LDA/HMPA combination was used to fragment aromatic thioacetals to form unsymmetrically substituted thiothionophthalicanhydrides (Scheme 3, eq 3). ... 

Davis FA, Gaspari PM, Nolt B, Xu P. Asymmetric synthesis of acyclic 1,3-amino alcohols by reduction of w-sulfinyl j6-amino ketones. Formal synthesis of ( )-pinidinol and (-f )-epipinidinol. J. Org. Chem. 2008 73(24) 9619-%26. 

A variant that eliminates the production of water and that has proved effective for esterification of hydroxy and aromatic amino acids involves the use of thionyl chloride instead of acid. At a low temperature, the alcohol reacts with the chloride, generating methyl sulfinyl chloride, which produces the ester, probably through the mixed carboxylic acid-sulfinic acid anhydride (Figure 3.18, B). p-Toluenesulfonyl chloride added to the acid and benzyl alcohol serves the same purpose in the preparation of benzyl esters. 

Asymmetric a-alkylation of amines was achieved applying an immobilized chiral sulfonamide (Scheme 12.29) [13, 40]. To synthesize auxiliary 76, a tertiary alcohol (73) was converted into Grignard reagent 74. Addition of sulfur dioxide and subsequent chlorination furnished the sulfinyl chloride 75. Reaction with (S)-2-amino-l,l,2-triphenylethanol, followed by reduction, hydroboration and... 

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