Diphenyl diamine-based phosphonyl imines attached by the N-isopropyl group in the auxiliary have been synthesized in good yields under convenient reaction conditions. These new chiral N-phosphonyl imines can react with glycine enolate smoothly to give chiral α-β diamino esters in good yields (72%-90%) and up to excellent diastereoselectivity (>99:1 dr). By treatment with HBr, the chiral auxiliary can be readily removed. The absolute structure has been unambiguously determined by converting a product to a known sample.
Bibliographical noteFunding Information:
This work was supported by the National Institutes of Health (Grant Nos. 1 RO3 DA026960-01), and Robert Welch Foundation (Grant No. D-1361)
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- Chiral N-phosphonyl imine
- Chiral phosphoramide
- Glycine enolate
- α-β diamino ester