Enantioselective Allylation of Cyclic and In Situ Formed N‐Unsubstituted Imines with Tetraol‐Protected Allylboronates. Issue 46 (29th October 2021) - Ullrich, Patrick
Abstract: Tetraol‐protected α ‐chiral allylboronates are utilized in diastereo‐ and enantioselective transformations of cyclic imines (up to 98 %, d.r . 97 : 3, e.r . 99 : 1). An application to in situ formed N ‐unsubstituted imines gives in a consecutive one‐pot sequence selective access to all four stereoisomers of the homoallylamine within minutes (up to 88 %, d.r . 81 : 19, e.r . 99 : 1). These results underline the usability, tuneability and stability of tetraol‐based allylboronates. Abstract : Bench‐stable and readily accessible allylboronates were utilized in fast and enantioselective allylation of cyclic aldimines and ketimines. The N ‐unsubstituted imine derived from benzaldehyde was generated in situ and directly transformed with the allylation reagent – excess of ammonia was tolerated. All four homoallylic amines could be accessed selectively.