Reactive EC(p-p)π-systems 53 [1]: Reactivity studies on perfluoro-2-arsapropene: [2+2]-cycloaddition reactions and quantum chemical calculations

✍ Scribed by Thomas Albers; Joseph Grobe; Duc Le Van; Andreas H. Maulitz; Ernst-Ulrich Würthwein

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 193 KB
• Volume: 16
• Category: Article
• ISSN: 1042-7163
• DOI: 10.1002/hc.20118

✦ Synopsis

Abstract

The extremely labile perfluoro‐2‐arsapropene F~3~CAsCF~2~ (1) has been generated by an improved pyrolysis process of Me~3~SnAs(CF~3~)~2~ and found to be stabilized by the presence of hexamethyldisiloxane and tert‐butylphosphaethyne, thus allowing (i) reactivity studies with alkyne derivatives like tBuCP, (iPr)~2~NCP, MeCCN(iPr)~2~, HCCOEt and (ii) a full NMR investigation of 1 (^19^F, ^13^C). Due to the instability of 1 and some of the products, the [2+2]‐cycloaddition reactions gave the expected arsaphospha‐ and arsa‐cyclobutene derivatives, respectively, in moderate to good yields, but in some cases contaminated with side and/or decomposition products. Unequivocal characterization of the novel compounds was accomplished by spectroscopic in‐ vestigations (^1^H, ^13^C, ^19^F, ^31^P NMR, IR, MS) supported by comparison with the data of the more stable phosphorus analogues. An interesting isomerization was observed for the 2‐dialkylamino‐4,4‐difluoro‐ 1‐trifluoromethyl‐1‐arsa‐3‐phospha‐2‐cyclobutenes yielding the more stable 3‐dialkylamino‐2,4‐difluoro‐ 1‐trifluoromethyl‐1‐arsa‐2‐phospha‐3‐cyclobutenes. Quantum chemical calculations [B3LYP/6‐311+ G(d,p)] of HAsCH~2~, F~3~CAsCF~2~, and F~3~CPCF~2~ were carried out to compare the length of the AsC double bond with the literature data and to elucidate substituent effects on its electronic structure. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:406–419, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20118