121783-48-0Relevant articles and documents
Bifunctional Iminophosphorane Catalyzed Enantioselective Sulfa-Michael Addition to Unactivated α-Substituted Acrylate Esters
Farley, Alistair J. M.,Sandford, Christopher,Dixon, Darren J.
supporting information, p. 15992 - 15995 (2016/01/15)
The highly enantioselective sulfa-Michael addition of alkyl thiols to unactivated α-substituted acrylate esters catalyzed by a bifunctional iminophosphorane organocatalyst under mild conditions is described. The strong Br?nsted basicity of the iminophosphorane moiety of the catalyst provides the necessary activation of the alkyl thiol pro-nucleophile, while the two tert-leucine residues flanking a central thiourea hydrogen-bond donor facilitate high enantiofacial selectivity in the protonation of the transient enolate intermediate. The reaction is broad in scope with respect to the alkyl thiol, the ester moiety, and the α-substituent of the α,β-unsaturated ester, affords sulfa-Michael adducts in excellent yields (up to >99%) and enantioselectivities (up to 96% ee), and is amenable to decagram scale-up using catalyst loadings as low as 0.05 mol %.
Convergent synthesis of a key intermediate for hypocholesterolemic agent 1233A, starting from methyl 3-hydroxy-2-methylpropanoate and asymmetrized bis(hydroxymethyl)acetaldehyde (BHYMA*)
Guanti, Giuseppe,Banfi, Luca,Schmid, Giovanna
, p. 4239 - 4242 (2007/10/02)
Compound 2, which is a known intermediate for the total synthesis of hypocholesterolemic agent 1233A 1, has been synthesized in good overall yield through a convergent approach, employing 3-hydroxy-2-methylpropanoate 6 and BHYMA* 5 as chiral building bloc