Synthesis, structures and properties of novel tricyclic tetraalkylphosphoranes with hydrogen and chlorine atoms at the apical position

Abstract

A tetraalkylhydrophosphorane having three methylene groups instead of three equatorial oxygen atoms of a 1-hydro-5-carbaphosphatrane was synthesized by the reaction of the corresponding phosphonium salt with LiAlH₄. A tetraalkylchloro- phosphorane was obtained from the phosphonium salt. Their X-ray crystallographic analyses showed that they have nearly ideal trigonal bipyramidal structures. Their bond lengths and angles as well as apical coupling constants showed that they have usual apicophilic arrangement. The tetraalkylhydrophosphorane gave two phosphine oxides, one of which was formed via homolytic bond cleavage of P-methine carbon bonds under daylight. Another phosphine oxide was estimated to be its isomer formed via the P-benzyl bond cleavage. The reaction of the chlorophosphorane with Me₃Al afforded the corresponding pentaalkylphosphorane with the methyl group.

Graphical Abstract

Keywords:

• Tetraalkylhydrophosphorane
• tetraalkylchlorophosphorane
• tripodal tetradentate ligand
• X-ray crystallographic analysis
• thioxophosphonate
• 1-hydro-5-carbaphosphatrane
• 1-hydro-6-carbaphosphatrane

Acknowledgment

We thank Professor Mao Minoura, Rikkyo University, for his advice for X-ray crystallography of 7.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was financially supported by a Grant-in-Aid for Scientific Research (No. 15105001, T.K.) from the Ministry of Education, Culture, Sports, Science and Technology, Japan.