Asymmetric synthesis of succinic semialdehyde derivatives.
The nucleophilic Michael addition of 2-(diphenylmethoxymethyl)-1-methyleneamino pyrrolidine 1Dto prochiral aliphatic and aromatic alkylidene malonates 2 takes place in the presence of MgI(2) to afford the corresponding Michael adducts 3 in excellent yields and good selectivities. In the aromatic series, optically pure (de > 98%) major diastereomers (S,S)-3 were isolated in good yields (77-93%) after chromatographic separation. Direct, racemization-free BF(3).OEt(2)-catalyzed thiolysis of compounds 3 afforded dithioacetals 7. These compounds were transformed into malonates 8 and succinic semialdehyde derivatives 9 by Raney Nickel mediated desulfuration or decarboxylation, respectively.
Lassaletta
José M
JM
Instituto de Investigaciones Químicas (CSIC-USe), Isla de la Cartuja, Americo Vespucio s/n, E-41092 Seville, Spain. jmlassa@cica.es
Vázquez
Juan
J
Prieto
Auxiliadora
A
Fernández
Rosario
R
Raabe
Gerhard
G
Enders
Dieter
D