[2+2] Cycloaddition and ring expansion reactions of cyclic phosphonium and aminophosphonium salts: synthesis and structure of the first eight-membered ylide-type heterocycles
A series of new eight-membered heterocycles, 4 and 6, was isolated from the reactions of simple six-membered aza-ylides with acetylene and nitrile derivatives. These structures were elucidated by X-ray crystal analysis. On the other hand, the reactions of five-membered ylides and aza-ylides with nitrile derivatives formed seven-membered ylides, which were hydrolyzed immediately during aqueous work-up to give phosphine oxide derivatives.
从简单的六元氮杂环与乙炔和腈衍生物的反应中分离出一系列新的八元杂环,即 4 和 6。这些结构通过 X 射线晶体分析得以阐明。另一方面,五元醯化物和氮杂环醯化物与腈衍生物反应生成七元醯化物,这些醯化物在水处理过程中立即水解,生成氧化膦衍生物。
Reactions of five and six membered cyclic phosphonium aza-ylids, 2a,b with phenyl thiobenzoate and aryl thiocinnamate gave acylated products 3 and 4. On the other hand, the reactions of 2a,b with phenyl alkenylthioesters gave compounds 5, 6, and 7.
REACTION OF CYCLIC AMINO PHOSPHONIUM SALTS WITH α-CHLOROVINYL SULFONE
A cyclic aza-ylide that was generated from 5- or 6-membered cyclic amino phosphonium salts 1a,b was reacted with alpha-chlorovinyl sulfone 3 in the presence of sodium hydride to give adducts 4a,b via the Michael addition followed by dehydrochlorination. The structure and formation pathways are discussed.
REACTIONS OF CYCLIC AZA-YLIDES WITH β-DICARBONYL COMPOUNDS
The reactions of five- and six-membered cyclic iminophosphoranes, 3 and 4, with P-dicarbonyl compounds gave enamino phosphine oxide derivatives 5a-h in good yields. Compounds 5b and 5e were stereoselectively converted to 1,6- and 1,7-diene 9a and 9b.
Synthesis and Aza-Wittig reactions of Cyclic Amino-phosphonium Salts