Reagents, organometallic inverse addition

Synthesis with addition of 2 G-atoms—Inverse addition of organometallic reagents s. 11, 895... 

Organometallic substitution of iron-complexed dioxolenes has been reported. The reaction proceeds with net inversion of configuration, the result of a two-step addition-elimination pathway. Dialkyl-cuprates, higher order cyanocuprates and Grignard reagents have all been employed, and sequential dis-... 

These subsequent reactions can be avoided by applying inversed-order addition, i.e., by adding the organometallic compound to the electrophilic reagent, the latter preferably used in excess. In this way excellent yields are obtained in the reactions of bis(methylthio)methyllithium with dimethyl disulfide and trimethylchlorosilane (compare Ref. [2]). 

Stannylation of dipole-stabiUzed cyclic tertiary benzylic a-oxycarbanions may occur with retention or inversion of stereochemistry depending on R and X of RsSnX used. Solvent and additive dependence of the high diastereoface selectivity observed for 1,2-additions of organometallic reagents to IV-f-butanesulflnylimines has been explored for aldimines and ketimines of different steric and electronic properties. ... 

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