General Routes to Alkyl Phosphatrioxaadamantane Ligands

Abstract

The secondary phosphine CgPH (CgP = 6-phospha-2,4,8-trioxa-1,3,5,7-tetramethyladamantyl group) is made in 50% yield by a modification of the literature method (avoiding high pressures of PH3) by bubbling PH3 through an acidified solution of 2,4-pentanedione at 0 °C. Under similar conditions the ethyl analogue EtCgPH is formed from 3,5-heptanedione in 75% yield. The halophosphines CgPCl and CgPBr are made by treatment of CgPH with N-halosuccinimide. CgPBr is also made by treatment of CgPH with Br2. Three methods are described for the synthesis of CgPR, where R = alkyl: (a) the previously reported acid-catalyzed condensation reaction of RPH2 with 2,4-pentanedione, which has been extended to R = iPr; (b) treatment of CgP(BH3)Li with RX followed by borane deprotection with Et2NH, which has been used for R = iPr, benzyl, n-C20H41; (c) treatment of CgPBr with RMgX, which has been used for R = iPr, Me. The complexes [PtCl2(CgPH)2] (1), [PdCl2(CgPH)2] (2), [PdCl2(CgPR)2] (where R = iPr (3a), Cy (3b)), and [PtCl2(CgPR)2] (where R = iPr (4a), Cy (4b), n-C20H41 (4c)) are described. The crystal structures of CgPH, CgPCl, [CgP(CH2Ph)2]Br, CgP(n-C20H41), and complexes 1, 3b, and 4c are reported. From the ν(CO) values for trans-[RhCl(CO)(CgPX)2], the σ-donor/π-acceptor properties of CgPX are in the order X = iPr > Me > Ph > H > Cl.

Platinum(II) complexes incorporating racemic and optically active 1-alkyl-3-phospholenes and 1-propyl-phospholane P-ligands: Synthesis, stereostructure, NMR properties and catalytic activity

“…Arylphospholes, 3-phospholenes, phospholanes, a 1,4-dihydrophosphinine and a 1,2,3,6-tetrahydrophosphinine were converted to the corresponding platinum complexes by Kollár and Keglevich [6e9]. Pringle et al described the platinum complexes of a few phospholanes, phosphinines and phosphepanes [10], as well as those of 9-phosphabicyclononanes (Phobanes) [11] and 6-phospha-2,4,8-trioxaadamantanes [12]. Among the bidentate heterocyclic P-ligands, DuPhos [13], PennPhos [14] and BIPNOR [15] are to be mentioned, but only DuPhos has been applied in platinum complexes [16e18].…”

Synthesis and use of borane and platinum(II) complexes of 3‐diphenylphosphino‐1‐ phenylphospholane (LuPhos)

“…Heterocyclic P-ligands occurring in Pt(II) complexes, comprise, among others [6][7][8], arylphospholes [9,10], phospholenes [11], phospholanes [11,12], phosphinine (phosphorine) derivatives [11,12], phosphepanes [12], as well as 9-phosphabicyclononanes (Phobanes) [13] and 6-phospha-2,4,8-trioxaadamantanes [14].…”

A new family of platinum(II) complexes incorporating five‐ and six‐membered cyclic phosphine ligands

“…As regard to cyclic phosphines, arylphospholes were transformed to the related platinum complexes by Kollár and Keglevich [4][5][6]. Pringle et al described the platinum complexes of a few phospholanes, phosphorin's, and phosphepanes [7], as well as 9-phosphabicyclononanes (Phobanes) [8] and 6-phospha-2,4,8-trioxaadamantanes [9]. Among the bidentate heterocyclic P-ligands, DuPhos [10], PennPhos [11], and BIPNOR [12] are well-known representatives, from among which only DuPhos has been applied in platinum complexes [13][14][15].…”