DIETHOXYMETHYLLITHIUM - GENERATION VIA TRANSMETALATION OF DIETHOXYMETHYLTRIBUTYLTIN, STABILITY, NUCLEOPHILIC REACTIVITY IN ADDITION-REACTIONS, AND USE AS A PRECURSOR OF GROUP-14 FORMYLMETALS

Diethoxymethyltributyltin and dimethoxymethyltributyltin have been con verted into the corresponding dialkoxymethyllithium reagents upon tran smetallation by n-butyllithium in THF. Temperature appears to be the k ey parameter controlling the decomposition of diethoxy- (or dimethoxy- ) methyllithium. Inside the reactor, -78-degrees-C appears to be the b orderline temperature to allow trapping experiments with electrophiles before decomposition. Nucleophilic addition on carbonyl derivatives h as been examined and the evaluation of stereochemical trends and regio chemical trends (1,2-/1,4-addition in the case of alpha,beta-enones) h as been used to characterize the chemical behavior of this type of rea gent. Furthermore, in the case of electrophilic trapping by chlorosila nes or chlorogermanes, the expected alpha-silyl or alpha-germylacetals have been obtained and their hydrolysis into group 14 formylmetals ha s been observed using electronic spectrometry.