Deoxygenation of isocyanates via transient electrophilic terminal phosphinidene complexes: Are strained P‐heterocycles involved?
Deoxygenation of isocyanates via transient electrophilic terminal phosphinidene complexes: Are strained P‐heterocycles involved?
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通过瞬态亲电末端膦亚胺配合物进行异氰酸酯脱氧：是否涉及紧张的 P-杂环？
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发表时间：
2011
期刊：
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通讯作者：
R. Streubel
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作者：
C. Schulten;G. V. Frantzius;G. Schnakenburg;R. Streubel
在异氰酸叔丁酯存在下，铬（1a）和钨（1b）的2h -氮磷配合物进行热分解，合成了1,3,2,4σ3λ3−二氧二磷酸烷配合物3a，b和4a，b；作为反应中间体，提出了3-亚胺-磷烷配合物8a，b，它们分解得到氧化磷二烯配合物9a，b。后者的中间作用是由交叉二聚实验推断出来的（2h -氮磷配合物1a，b与异氰酸叔丁酯的1:1混合物分解），它提供了混合金属双核顺式和反式配合物5a/b和6a/b。核磁共振31P谱显示副产物形成[双（三甲基硅基）甲基]氰膦配合物11a，b。配合物1b与体积较小的异氰酸乙酯发生热反应，得到了新型的1,3,4σ3λ3-重氮膦-5-亚胺-2- 1配合物7与配合物3b和4b。对于后一种情况，3-亚氨基-草磷烷（12）和氮磷啶-3- 1（13）配合物被提议作为反应中间体。所有的最终产物都通过多核核磁共振波谱、红外光谱、质谱以及配合物3b和4a、b的单晶x射线晶体学进行了表征。DFT计算有力地支持了3-亚氨基-磷烷配合物12的瞬态形成和分解，生成9b和异腈。氮杂膦-3- 1配合物13被计算表征为甲基模型。根据计算，最终产物1、3、2、4σ3λ3-二氧膦配合物3a、b和4a、b是由瞬态末端氧化膦配合物9a、b二聚化形成的。©2011 Wiley期刊公司杂原子化学，2011 (2):275 - 286；请登录wileyonlinelibrary.com在线阅读本文。DOI 10.1002 / hc.20677
Synthesis of 1,3,2,4σ3λ3−dioxadiphosphetane complexes 3a,b and 4a,b was achieved via thermal decomposition of 2H-azaphosphirene complexes of chromium (1a) and tungsten (1b) in the presence of tert-butyl isocyanate; as reactive intermediates 3-imino-oxaphosphirane complexes 8a,b are proposed, which decompose to give phosphinidene oxide complexes 9a,b. The intermediacy of the latter is inferred from a cross-dimerization experiment (decomposition of a 1:1 mixture of 2H-azaphosphirene complexes 1a,b with tert-butyl isocyanate), which furnished the mixed metal dinuclear cis and trans complexes 5a/b and 6a/b. 31P NMR spectroscopy revealed the formation of [bis(trimethylsilyl)methyl]cyanophosphane complexes 11a,b as by-products. Thermal reaction of complex 1b with the less bulky ethyl isocyanate furnished the novel 1,3,4σ3λ3-diazaphospholidin-5-imin-2-one complex 7 together with complexes 3b and 4b. For the latter case, 3-imino-oxaphosphirane (12) and azaphosphiridin-3-one (13) complexes are proposed as reactive intermediates. All final products were characterized by multinuclear NMR spectroscopy, IR, MS, and single-crystal X-ray crystallography in the cases of complexes 3b and 4a,b. DFT calculations strongly support the transient formation and decomposition of 3-imino-oxaphosphirane complex 12 to form 9b and isonitrile. Azaphosphiridin-3-one complex 13 was characterized computationally as the methyl model. In accordance with the calculations, final products 1,3,2,4σ3λ3-dioxadiphosphetane complexes 3a,b and 4a,b form by dimerization of transient terminal phosphinidene oxide complexes 9a,b. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:275–286, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20677