The Lloyd-Jones Research Group

Synthesis and Stereodynamics of
Chiral "Proton Sponges"

We have recently prepared a C₂-symmetric N,N-chiral proton sponge.We have the X-ray crystal structure of the protonated form. The synthesis is high yielding - 57 % from 1,8-diamino-naphthalene. At equilibrium, the chiral diastereomer is present in excess over the meso. (ca. 9/1 ratio). NMR studies (variable T, chiral media, 2D and nOe) are being used to study the structure and stereodynamics of the protonated and non-protonated systems. From these studies we hope to determine an upper limit for the hydrogen bond strength in the systems. These novel chiral bases and cations may have use as reagents, catalysts and modifiers in organic synthesis.

References:

• "Synthesis of a protonated C₂-Symmetric N,N-chiral "Proton Sponge", Jonathan P. H. Charmant, Guy C. Lloyd-Jones, Torren M. Peakman and Robert L. Woodward, Tetrahedron Lett., 1998, 39, 4733-4736.
• "Stereodynamic and Structural Studies of the Suprisingly Weak Hydrogen Bond in the Protonated form of an N,N-Chiral 'Proton Sponge'", Jonathan P. H. Charmant, Guy C. Lloyd-Jones* Torren M. Peakman and Robert L. Woodward, manuscript in preparation.

This project is being funded by a Nuffield Foundation Newly Appointed Science Lecturers Grant (SCI/180/96/142/G) 1997-1999 and by a CASE award from Pfizer (1998 - 2001).