588731-97-9

Upstream product

• 1026780-00-6 C₁₇H₂₆O₃Si 
• 638-10-8 ethyl 3-methylbut-2-enoate 

Downstream Products

• 118918-39-1 (+)-(4R)-4-acetyloxy-4-phenyl-2-butanone 

Relevant academic research and scientific papers

Catalytic asymmetric formation of δ-Lactones from Unsaturated acyl halides

Previously unexplored enantiopure zwitterionic ammonium dienolates have been utilized in this work as reactive intermediates that act as diene components in hetero-Diels-Alder reactions (HDAs) with aldehydes to produce optically active δ-lactones, subunits of numerous bioactive products. The dienolates were generated in situ from E/Z mixtures of a,b- unsaturated acid chlorides by use of a nucleophilic quinidine derivative and Sn (OTf)2 as co-catalyst. The latter component was not directly involved in the cycloaddition step with aldehydes and simply facilitated the formation of the reactive dienolate species. The scope of the cycloaddition was considerably improved by use of a complex formed from Er- (OTf)3 and a simple commercially available norephedrine-derived ligand that tolerated a broad range of aromatic and heteroaromatic aldehydes for a cooperative bifunctional Lewis-acid-/ Lewis-base-catalyzed reaction, providing a,b-unsaturated d-lactones with excellent enantioselectivities. Mechanistic studies confirmed the formation of the dienolate intermediates for both catalytic systems. The active ErIII complex is most likely a monomeric species. Interestingly, all lanthanides can catalyze the title reaction, but the efficiency in terms of yield and enantioselectivity depends directly on the radius of the Ln III ion. Similarly, use of the pseudolanthanides ScIII and YIII also resulted in product formation, whereas the larger La III and other transition metal salts, as well as main group metal salts, proved to be inefficient. In addition, various synthetic transformations of 6- CCl3- or 4-silyl-substituted α,β-unsaturated d-lactones, giving access to a number of valuable δ-lactone building blocks, were investigated.

Lewis acid-lewis base catalyzed enantioselective hetero-diels-alder reaction for direct access to δ-lactones

A complex formed In situ from Er(OTf)3 and a simple commercially available norephedrine ligand promotes an unprecedented [4 + 2] cycloaddition of α,β-unsaturated acid chlorides with a broad range of aromatic and heteroaromatic aldehydes by a cooperative bifunctional Lewis acid-Lewis base catalytic mode of action providing valuable δ-lactone building blocks with excellent enantioselectivity.

Lewis base activation of Lewis acids: Catalytic, enantioselective addition of silyl ketene acetals to aldehydes

The concept of Lewis base activation of Lewis acids has been reduced to practice for catalysis of the aldol reaction of silyl ketene acetals and silyl dienol ethers with aldehydes. The weakly acidic species, silicon tetrachloride (SiCl4), can b

Lewis base activation of Lewis acids. Vinylogous aldol reactions

A highly regioselective vinylogous aldol reaction catalyzed by SiCl4 and a chiral phosphoramide (R,R)-5, providing δ-hydroxy enones for a variety of aldehyde and dienol ether structures, has been developed. Low catalyst loadings (1 mol %) can b