102341-05-9

Upstream product

• 336182-94-6 (2S,3S,4S)-4-Benzyloxy-3-hydroxy-2-methyl-pentanoic acid (S)-3-phenyl-2-(toluene-4-sulfonylamino)-propyl ester 
• 479483-99-3 (2S,3S,4S)-4-Benzyloxy-3-hydroxy-2-methyl-pentanoic acid (S)-3-methyl-2-(toluene-4-sulfonylamino)-butyl ester 
• 131793-65-2 N-<(2R,3R,4S)-4-(benzyloxy)-3-hydroxy-2-methylpentanoyl>-(1R,2S,6R,7S)-1,10,10-trimethyl-4-oxo-5-aza-3-oxatricyclo<5.2.1.0^2,6>decane 

Downstream Products

• 94989-84-1 (2S,3S,4S)-4-benzyloxy-3-hydroxy-2-methyl-pentanoic acid methyl ester 

Relevant academic research and scientific papers

Chelation-controlled ester-derived titanium enolate aldol reaction: Diastereoselective syn-aldols with mono- and bidentate aldehydes

A chelation-controlled and highly diastereoselective synthesis of syn-aldols is described. Aldol reaction of (S)-valinol-derived ester with a variety of aldehydes proceeded with high syn-diastereoselectivities (up to 99:1) and isolated yields (94%).

Ester derived titanium enolate aldol reaction: Chelation controlled diastereoselective synthesis of syn-aldols

A chelation controlled and highly diastereoselective synthesis of syn-aldols is described. Aldol reaction of commercially available L-phenylalaninol derived esters with a variety of bidentate oxyaldehydes proceeded with excellent syn-diastereoselectivities and isolated yields.

Asymmetric aldol reactions. A new camphor-derived chiral auxiliary giving highly stereoselective aldol reactions of both lithium and titanium(IV) enolates

A new, conformationally rigid camphor-derived N-propionyloxazolidinone effects asymmetric stereochemical control in syn-selective aldol condensations of the derived lithium and titanium(IV) enolates with a variety of aldehydes. Simple and diastereofacial selectivities of the reaction are high, and diastereomeric purities of the crude aldol adducts can be improved, usually by a single recrystallization, to levels of 98-99% in most cases. The observed facial selectivity is best explained by a transition structure in which intramolecular chelation between the oxazolidinone carbonyl oxygen and the metal induces an enolate π-facial differentiation; the major products observed are those expected from chelation control. Hydrolysis of the exocyclic carbonyl of the aldol adducts led to β-hydroxy-α-methylcarboxylic acids, with recovery of the chiral auxiliary. Consonant double-asymmetric induction with (R)-2-(benzyloxy)propanal gave the product expected from oxazolidinone chelation but nonchelation of the aldehyde benzyloxy group.