Synthesis and structural aspects of N-triflylphosphoramides and their calcium salts--highly acidic and effective Brønsted acids

Magnus Rueping; Boris J Nachtsheim; René M Koenigs; Winai Ieawsuwan

doi:10.1002/chem.201001438

Synthesis and structural aspects of N-triflylphosphoramides and their calcium salts--highly acidic and effective Brønsted acids

Chemistry. 2010 Nov 22;16(44):13116-26. doi: 10.1002/chem.201001438.

Authors

Magnus Rueping¹, Boris J Nachtsheim, René M Koenigs, Winai Ieawsuwan

Affiliation

¹ RWTH Aachen University, Institute of Organic Chemistry, Landoltweg 1, 52074 Aachen, Germany. magnus.rueping@rwth-aachen.de

PMID: 20922721
DOI: 10.1002/chem.201001438

Abstract

Recently, 1,1'-bi-2-naphthol (BINOL)-based N-triflylphosphoramides emerged as a new class of potent Brønsted acid catalysts. In this paper we describe the efficient synthesis of various BINOL-based N-triflylphosphoramides and their calcium salts. Furthermore, X-ray crystal structure analysis combined with energy-dispersive X-ray spectroscopy (EDX) measurements confirmed that the synthesised chiral N-triflylphosphoramides are highly acidic metal-free catalysts.