Réactivité des dialcoyl(trialcoylgermyl)phosphines avec divers dérivés carbonylés

Abstract

Aldehydes condense on the germaniumphosphorus bond of diethyl(triethylgermyl)phosphine with opening of the CO double bond and formation of phosphorus alkoxygermanes of the structure GeOCHP. The insertion derivatives of chloral and bromal are unstable and decompose via a β-elimination process. The addition of dialkylketones is far more difficult and only the ketones with a little hindered carbonyl group, such as cyclopentanone, or those activated by electron-attracting groups, such as hexafluoro-, hexachloroacetone, 1,1,3,3-tetrafluoro-1,3-dichloro- or 1,3,3-trifluoro-1,1,3-trichloropropanone lead to insertion derivatives which are not very stable [with the exception of (CF 3) 2CO], which have been characterized by their transposition, decomposition, oxidation or hydrolysis products. α-Ethylenic aldehydes and ketones such as crotonaldehyde, cinnamaldehyde and 2-cyclopentene- 1 -one give 1,4-dipolar additions on their conjugated system, with formation of phosphorus enoxygermanes; hydrolysis of these derivatives leads to γ-phosphorus aldehydes or ketones. An addition mechanism involving an ionic cleavage of the germaniumphosphorus bond is considered. Ketenes insert in the germaniumphosphorus bond through an exclusive opening of the carbonyl group. Hydrolysis of the phosphorus enoxygermanes which are thus formed leads to “α-phosphoryl-ketones” which are also isolated by the action of germylphosphines on acid anhydrides.