New Synthetic Routes to β-Olefinic Triphenylphosphonium Salts via (Diolefin)tricarbonyliron Complexes

✍ Scribed by Albrecht Salzer; Andreas Hafner

• Publisher: John Wiley and Sons
• Year: 1983
• Tongue: German
• Weight: 558 KB
• Volume: 66
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19830660616

✦ Synopsis

The available experimental evidence suggests that, in general, nucleophilic attack of tertiary phosphines at the hydrocarbon moiety (path a) should be the kinetically most favoured process under mild conditions [5] [6]. A number of olefinic phosphonium salts have been isolated in this manner with various metalcoordinated n-bonded hydrocarbon ligands [2].

Phosphonium salts, when used for Wittig reactions, have wide synthetic use [7], especially in the syntheses of natural products [8]. The above addition reactions suggest interesting alternatives for the preparation of p-olefinic phosphonium salts, which are difficult to obtain by conventional unequivocal routes. The purpose of this study was to explore the stereo-and regioselective potential of this reaction and to extend the number of metal-coordinated olefinic phosphonium salts available. A further aim was to develop methods for decomplexation and isolation of the free organic moieties.

2. Results and Discussion. -2.1 Formation of (2-En-1-y1)phosphonium Salts. A preliminary communication by Whitesides et al. [9] reported on the formation of cis-allylphosphonium salts from organometallic n-complexes. The system involved the use of (1-3-~-allyl)tetracarbonyliron cations, readily available in high yield Scheme 2 2 a 3a