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• 作者：Alex S. Ionkin ; William J. Marshall ; Brian M. Fish ; Alexander A. Marchione ; Laurie A. Howe ; Fredric Davidson ; Charles N. McEwen
• 刊名：Organometallics
• 出版年：2008
• 出版时间：October 13, 2008
• 年：2008
• 卷：27
• 期：19
• 页码：5118-5121
• 全文大小：152K
• 年卷期：v.27,no.19(October 13, 2008)
• ISSN：1520-6041

文摘

1-Methyl-3,5-bis(2,4,6-tri-tert-butylphenyl)-1H-[1,2,4]triphosphole (6) and 1-benzyl-3,5-bis(2,4,6-tri-tert-butylphenyl)-1H-[1,2,4]triphosphole (7) were synthesized and isolated with among the most planar and least sterically hindered σ³,λ³-phosphorus atoms, which are an indication of the aromaticity of this heterocycle. The sums of the bond angles at the σ³,λ³-phosphorus atoms in 6 and 7 are close to 360°. σ³,λ³-Phosphorus atoms in 6 and 7 have substantial deshielded chemical shifts at 151.86 and 161.71 ppm in the ³¹P NMR spectra. The parental trimethylphosphine and tribenzylphosphine with pyramidal phosphorus atoms have chemicals shifts at −62.0 and −10.4 ppm. There are large P−P coupling constants: ¹J_PP = 549.7 Hz for 6 and 553.3 Hz for 7. This is further evidence of a significant delocalization of the electron density in these polyphosphorus heterocycles. Compound 7 reacts with sulfur to afford 3-benzyl-2,4-bis(2,4,6-tri-tert-butylphenyl)-6,7-dithia-1,3λ⁵,5-triphosphabicyclo[3.1.1]hepta-2,3-diene 1,5-disulfide (8), which is the first example of a C₂P₃S₄ folded heterocycle. The formation of 8 involves an unusual 1,3-benzyl shift with oxidation of all λ³-phosphorus atoms to λ⁵-phosphorus atoms.