Synthetic Entry into 1-Phosphono-3-azabicyclo[3.1.0]hexanes
摘要:
3-Azabicyclo[3.1.0]hex-2-en-1-yl phosphonates were prepared in a five-step reaction route from beta-ketophosphonates. The key steps in this sequence are an atom-transfer radical cyclization and an unforeseen lithium halogen exchange with n-BuLi. The cyclization reaction proceeds with excellent diastereoselectivity. The resulting cyclic imines were reduced, and 3-azabicyclo[3.1.0]hexan-1-yl phosphonates were obtained.
Preparation of Tetrasubstituted 3-Phosphonopyrroles through Hydroamination: Scope and Limitations
作者:Wouter Debrouwer、Thomas S. A. Heugebaert、Christian V. Stevens
DOI:10.1021/jo500139z
日期:2014.5.16
Phosphonylated pyrroles were obtained by a ZnCl2-catalyzed 5-exo-dig hydroamination of propargylic enamines. These starting compounds were obtained in two steps from commercially available beta-ketophosphonates. The method tolerates a wide variety of substituents at the 1,2- and 5-position of the pyrrole, while further derivatization allows for the introduction of substituents at the 4-position via lithiation or halogenation.