Highly Enantio‐ and Diastereoselective Synthesis of Chiral α‐Alkylisoserine Derivatives
Zhiqiang Han, Wenguo Yang, Choon‐Hong Tan and Zhiyong Jiang
Advanced Synthesis and Catalysis, 2013, 355, 1505 – 1511
Abstract: The first organocatalytic Mannich reaction of 5H‐oxazol‐4‐ones with various readily prepared aryl‐ and alkylsulfonimides has been developed. Two commercially available pseudoenantiomeric Cinchona alkaloids‐derived tertiary amine/ureas have been demonstrated as the most efficient catalysts to access the opposite enantiomers of the Mannich products with equally excellent enantio‐ and diastereoselectivities. From the Mannich adducts, important α‐methyl‐α‐hydroxy‐β‐amino acid derivatives, such as the α‐methylated C‐13 side chain of taxol and taxotere, can be conveniently prepared.
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