Two expedient methods for the preparation of chiral diamines
A study on the development of methodology for the synthesis of chiral diamines is reported. Two synthetic approaches are described both of which involve the generation and subsequent reaction of aziridinium ions. One of the methods is a one-pot preparation from (R)-styrene oxide to give several diamines and a C2 symmetric triamine in yields of 63–93%. The other method is a sequential two-step approach from (R)- or (S)-phenylglycinol and four diamines have been prepared in yields of 62–82%. Both approaches start from readily available materials and are simple, high yielding, and shorter than previous synthetic routes and can be used to prepare either enantiomer of a range of chiral diamines. Such chiral diamines are useful reagents for asymmetric synthesis and are intermediates in the preparation of non-opioid analgesics.