51122-89-5Relevant 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.
, 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 %.
Preparation of 1,1-disubstituted ethylene compounds
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, (2008/06/13)
1,1-disubstituted ethylene compounds of the general formula I STR1 where Z is COOR2, CN or COR3, R1 is an aliphatic, cycloalophatic, araliphatic, aromatic or heterocyclic radical which may be further substituted by functional groups which are inert under the reaction conditions, R2 is an aliphatic, cycloaliphatic or araliphatic radical of 1 to 15 carbon atoms and R3 is an aliphatic, cycloaliphatic or araliphatic radical of 1 to 15 carbon atoms which may be substituted by groups which are inert under the reaction conditions, and R1 together with R2 or R1 together with R3 may furthermore form an alkylene chain of 2 to 10 carbon atoms which may be substituted by groups which are inert under the reaction conditions, are prepared from a formyl compound of the general formula II STR2 where Z, R1, R2 and R3 have the above meanings, by a process in which the reaction is carried out in the presence of formaldehyde or paraformaldehyde and (a) a C1 -C12 -alkanol or (b) a mixture of a C1 -C12 -alkanol and water or (c) with water in the presence of a secondary amine and a protic acid at from 0° to 200° C.
Methyl 4-Oxothiolane-3-carboxylate and Methyl 2-Methyl-4-oxothiolane-3-carboxylate Anions as Synthetic Equivalents of α-Acrylate and α-Crotonate Anions. Formal Synthesis of Integerrinecic Acid
Baraldi, Pier Giovanni,Guarneri, Mario,Pollini, Gian Piero,Simoni, Daniele,Barco, Achille,Benetti, Simonetta
, p. 2501 - 2505 (2007/10/02)
The base-promoted fragmentation of the C-alkylation products (6a-h) and (8a-e) of methyl 4-oxothiolane-3-carboxylate (4) and methyl 2-methyl-4-oxothiolane-3-carboxylate (5) gave good yields of the α-substituted acrylates (7a-h) and α-substituted crotonate
