Efficient Synthesis of Dissymmetric Malonic Acid S,O-Esters via Monoalcoholysis of Symmetric Dithiomalonates under Neutral Conditions
摘要:
A novel method for the highly selective synthesis of dissymmetric S,O-malonates starting from symmetric diphenyl dithiomalonates under neutral conditions is described. The key step is the thermal formation of an acylketene, the stability of which would contribute to the selectivity. The synthetic utility of the dissymmetric S,O-malonates is also shown.
Efficient Synthesis of Dissymmetric Malonic Acid S,O-Esters via Monoalcoholysis of Symmetric Dithiomalonates under Neutral Conditions
摘要:
A novel method for the highly selective synthesis of dissymmetric S,O-malonates starting from symmetric diphenyl dithiomalonates under neutral conditions is described. The key step is the thermal formation of an acylketene, the stability of which would contribute to the selectivity. The synthetic utility of the dissymmetric S,O-malonates is also shown.
A series of novel l-proline derived tertiary amine bifunctional organocatalysts 9 are reported, which were applied to the asymmetric Michaeladdition of dithiomalonates 2 to trans-β-nitroolefins 1. The reaction proceeded in high yields (up to 99%) with high enantioselectivities (up to 97% ee). The synthetic utility of this methodology was demonstrated in the short synthesis of (R)-phenibut in high