Synthesis and Application of a Bidentate Ligand Based on Decafluoro‐3‐phenyl‐3‐pentanol: Steric Effect of Pentafluoroethyl Groups on the Stereomutation of O‐Equatorial C‐Apical Spirophosphoranes

Abstract

1,1,1,2,2,4,4,5,5,5-Decafluoro-3-phenyl-3-pentanol was prepared by a Cannizzaro-type disproportionation reaction, and the dimetallated compound was used as a bidentate ligand, which is bulkier than the Martin ligand (1,1,1,3,3,3-hexafluoro-2-phenyl-2-propanol). A P-H spirophosphorane was synthesized by utilizing the new bidentate ligand, and the structure of the product was essentially the same as that of the P-H phosphorane with Martin ligands. Phosphoranes that exhibit reversed apicophilicity (O-equatorial) were also synthesized and could be converted into the corresponding stable stereoisomers (O-apical). The crystal structures of O-equatorial phosphoranes and the O-apical isomers were slightly affected by the steric repulsion of pentafluoroethyl groups. Kinetic measurements revealed that the stereomutation of O-equatorial methylphosphorane to the O-apical isomer was slowed. The activation enthalpy for the stereomutation of the former to the latter was higher than that of the phosphorane with Martin ligands by 5.1 kcal mol(-1).

Synthesis, structure, and reaction of tricoordinate stibine and tetracoordinate stiboranide

“…Interconversion between 1 and 2. which acted as oxidative cyclization (Scheme 3) [38,42]. The antiapicophilic compounds could quantitatively convert into the corresponding apicophilic compounds by heat in solution [38,42]. Furthermore, the kinetic study revealed that the steric hindrance of the C 2 F 5 group was more effective for freezing pseudorotation [38,42].…”

“…Interconversion between 1 and 2. which acted as oxidative cyclization (Scheme 3) [38,42]. The antiapicophilic compounds could quantitatively convert into the corresponding apicophilic compounds by heat in solution [38,42].…”

“…Using Martin ligand [37] and new bidentate ligand with two C 2 F 5 groups [38], synthesis, structure, and reaction of pentacoordinate compounds in the central atom of phosphorus and arsenic had been reported [20,[38][39][40][41][42][43]. Herein, we now report the synthesis of tricoordinate stibine 1 and a unique tetracoordinate stiboranide 2a bearing new bidentate ligand.…”

Chiral Hypervalent, Pentacoordinated Phosphoranes

“…More recently, studies on spirophosphoranes, prepared from a new bulkier analogue of the Martin ligand containing two decafluoroetyl units, have been carried out by the Yamamoto group. This new ligand was expected to suppress BPR more efficiently than the Martin ligand [84]. The synthesis of P-H-spirophosphoranes 75a,b was based on a two-step reaction involving dimetallation of perfluorocumyl alcohol derivatives leading to the corresponding dianion and its subsequent condensation with PCl3, followed by acidification with 6 molar HCl.…”

Reaction of 5-oxo-2-phenyl-4,4-bis(trifluoromethyl)-4,5-dihydro-1,3,2-benzodioxaphosphepine with chloral. The synthesis and spatial structure of 5-carbaphosphatrane containing a four-membered ring

“…That is why their synthesis, reactivi ties, and configurational stabilities are under intensive study. [1][2][3][4][5][6][7][8][9][10][11][12] The benzodioxaphosphole fragment stabilizes the pentacoordinated state of phosphorus most efficient ly. 5 Taking this into account, we have proposed a new approach to the preparation of phosphoranes that involves reactions of activated carbonyl compounds with benzo dioxaphospholes containing the tricoordinated P atom and a carbonyl or imino group in the γ or δ position relative to the P atom in the endocyclic substituent.…”