Stereodivergent Synthesis of Iminosugars from Stannylated Derivatives of (S)-Vinylglycinol
摘要:
An original access to iminosugars from a cis/trans mixture of stannylated oxazolidinones 5 is reported. The dehydropiperidines 7-trans and 7-cis were obtained stereoselectively with an RS and SS configuration depending on the order of the Sn-Li transmetalation (followed by electrophilic trapping) and of the ring closing metathesis reactions due to the stereoselective epimerization of the alpha-aminoanion intermediate. The dehydropiperidines 7-trans and 7-cis were subsequently used for the synthesis of enantiopure homonojirimycin analogs.
Sn−Li Transmetalation of α‐Aminoorganostannanes for the Stereoselective Synthesis of Substituted Dehydropiperidines and Dehydroazepanes
作者:Alexandre Lumbroso、Isabelle Beaudet、Jean‐Paul Quintard、Cécile Fraisse、Nicolas Galland、Loïc Toupet、Erwan Le Grognec
DOI:10.1002/adsc.201900349
日期:2019.8.21
A highly diastereoselective synthesis of (R,S) or (S,S) 2,6‐disubstituted dehydropiperidines and 2,7‐disubstituted dehydroazepanes has been developed. The stereochemicalpreference for the (R,S) or the (S,S) isomer is governed by a tin‐lithium exchange/electrophilic trapping sequence combined with a ring‐closing metathesis. Their relative order was found to have a dramatic influence on the interaction