Rasta Resin-PPh 3-NBniPr2 and its use in one-pot wittig reaction cascades

Abstract

A new triarylphosphine-tertiary amine bifunctional polymeric reagent has been prepared and used effectively in a variety of one-pot Wittig reactions. The design of this reagent resolved a deficiency of a previously reported related material, and allowed it to perform more efficiently in such reactions. Furthermore, it was readily recyclable, and was also successfully applied in cascade processes involving one-pot Wittig reactions followed by either a conjugate reduction or a reductive aldol reaction. In these reaction cascades, the phosphine oxide groups generated in the Wittig reaction served as the catalyst for the subsequent reaction. All in one pot! A recyclable, second-generation heterogeneous bifunctional polymer bearing phosphine and amine groups has been synthesized and showed enhanced utility in one-pot Wittig reactions compared to a previously reported related material. This polymer was also used in Wittig reaction cascade processes in which the oxidized polymer formed in the one-pot Wittig reaction served as the catalyst in a subsequent conjugate reduction or reductive aldol reaction (see scheme). © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.