Selective C-2 opening of 2,3-epoxyesters with HN3-amine system: A viable route to β-hydroxy-α-amino acids

✍ Scribed by Seiki Saito; Nobuyosi Takahashi; Teruhiko Ishikawa; Toshio Moriwake

• Publisher: Elsevier Science
• Year: 1991
• Tongue: French
• Weight: 306 KB
• Volume: 32
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)74855-6

✦ Synopsis

The combination of hydrogen azide with amines has proven to effect the C-2 opening of 2,3-epoxyester with high regioselectivity uniformly for trans-epoxyesters and depending on their structures for cis-ZJ-epoxyesters .

An important breakthrough has recently been achieved by Sharpless with regard to a very strong preference for nucleophilic attack on C-3 of 2,3-epoxy alcohols, acids, and amides by the aid of Ti(O-i-Pr)r-mediated epoxide activation. 1 He has also reported that diethylamine attacks the C-2 position of 2,3-epoxy acids,lb which can provide phydroxy-a-amino acids, albeit limiting to an N,N-disubstituted type. While cognizant of these encouraging developments, we have perceived a need for a general method for C-2 opening of the related structures, in particular, with respect to an introduction of azido-group into C-2 of 2,3-epoxyesters (Scheme I) because it can apparently appeal prospect for a straightforward access to P_hydroxy-a-amino acids of biological interests.2 Scheme I.