General routes to alkyl phosphatrioxaadamantane ligands

Joanne H. Downing, Joelle Floure, Katie Heslop, Mairi F. Haddow, Jonathan Hopewell, Matteo Lusi, Hirahataya Phetmung, A. Guy Orpen, Paul G. Pringle, Robert I. Pugh, Damaris Zambrano-Williams

Research output: Contribution to journalArticle (Academic Journal)peer-review

26 Citations (Scopus)

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 degrees C. Under similar conditions the ethyl analogue (Et)CgPH 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 Br-2. 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 = Pr-i; (b) treatment of CgP(BH3)Li with RX followed by borane deprotection with Et2NH, which has been used for R = Pr-i, benzyl, n-C20H41; (c) treatment of CgPBr with RMgX, which has been used for R = Pr-i, Me. The complexes [PtC12(CgPH)(2)] (1), [PdCl2(CgPH)(2)] (2), [PdCl2(CgPR)(2)] (where R = Pr-i (3a), Cy (3b)), and [PtCl2(CgPR)(2)] (where R = Pr-i (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 v(CO) values for trans-[RhCl(CO)(CgPX)(2)], the sigma-donor/pi-acceptor properties of CgPX are in the order X = Pr-i > Me > Ph > H > Cl.

Translated title of the contributionGeneral Routes to Alkyl Phosphatrioxaadamantane Ligands
Original languageEnglish
Pages (from-to)3216 - 3224
Number of pages9
JournalOrganometallics
Volume27
Issue number13
DOIs
Publication statusPublished - 14 Jul 2008

Bibliographical note

Publisher: ACS Publications

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