Study on Synthesis and Structure of Sterically Demanding 6-Phosphafulvenes

Abstract

t-Butylcyclopentadienyllithium was allowed to react with (2,4,6-tri-t-butylphenyl)phosphonous dichloride to afford the corresponding chloro-5-cyclopentadienylchlorophosphine as a mixture of diastereomers, the structure of one of which was determined by X-ray crystallography. The mixture of 5-cyclopentadienylchlorophosphine diastereomers was treated with a base to furnish novel 2-t-butyl-6-(2,4,6-tri-t-butylphenyl)-6-phosphafulvenes, and each geometrical isomer of them was fully characterized by X-ray crystallography. The E/Z ratio of the 6-phosphafulvene obtained was considerably dependent on the diastereomeric ratio of the chlorophosphine precursor.

Keywords:

• Chlorophosphines
• elimination
• fulvenes
• phosphaalkenes
• steric protection
• X-ray crystallography

Dedicated to Professor Marian Mikołajczyk from the CBMiM PAN in Łódź, Poland, on the occasion of his 70th birthday.

This work was supported in part by Grants-in-Aid for Scientific Research (No. 13304049 and 14044012) from the Ministry of Education, Culture, Sports, Science and Technology, Japan.

The present affiliation for Shigekazu Ito is Tokyo Institute of Technology, Tokyo, Japan and the present affiliation for Masaaki Yoshifuji is Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama, USA.