Synthesis of acyltrialkylgermanes and reactions with carbon nucleophiles

Acyltrialkylgermanes 4 have been obtained in good yields by the Swern oxidation of trialkyl(1-hydroxyalkyl)germanes 3 which were prepared from aldehydes 1 and trialkylgermyllithium 2. Reaction of 4 with butyllithium 5, tert-butyl lithioacetate 7 or 2-lithiopropionitrile 9 gave the respective 1,2-addition products 6, 8 and 10. However, reaction with 1-lithioethyl phenyl sulfone 11 gave α-(trialkylgermyl) ketones 12, and with the lithium enolate of tert-butyl bromoacetate 14 gave (trialkylgermyl)oxiranes 15 as the main products, respectively. The results of the treatment of 15 with Lewis acids are also discussed.