Crystal structure and reactivity of a pentacoordinate 1,2-oxastannetanide: an intermediate of the tin-Peterson reaction

gem-Heterosubstituted (stannyl)methylsilanes as synthetic equivalents of functionalized α-stannyl(methyl) anions

“…In fact, olefins arise from stereospecific elimination of R3SnOH from adducts 2, which are obtained as mixture of threo and erythro stereoisomers. Although a syn-or anti-elimination can occur, under the above described basic conditions, and based on the previously reported results, [8][9][10] olefins should be formed via a syn-elimination from the less hindered adduct threo-2, affording predominantly E-alkenes (Scheme 2). This reaction thus appears as a novel one-pot synthesis of alkenes via the tin-Peterson olefination.…”

“…On the other hand, as described above, phenylthio(methyl)stannanes can be metalated and further reacted with aldehydes to afford the corresponding -hydroxy adducts. 6,8,9 Thus, due to the advantages of the fluoride induced reactivity of the C-Si bond, in terms of mildness and absence of toxic co-solvents like HMPA, we studied the possible selective functionalization of the silicon moiety of [(phenylthio)(stannyl)methyl]silanes 1a-c, bearing different stannylated groups. We initially performed the reaction of 1a with benzaldehyde in the presence of TBAF (tetra-n-butylammonium fluoride) (1 eq.)…”

“…The so obtained results are in line with what reported by other authors on this kind of reactions. In fact, it has been observed [8][9][10] that the formation of olefins from -phenylthio--hydroxystannes occurs under acid conditions or by heating. In our procedure, taking advantage of the C-Si functionalization, we may state that room temperature was sufficient to promote the deoxystannylation, thus leading directly to the alkenylsulfides 3.…”

“…6 -Phenylthio--hydroxystannanes, formed by addition of suitables anions (-phenylthio(triphenylstannyl)methyllithium or lithium benzenethiolate) with benzaldehyde or epoxides, behaved as intermediates to prepare thio-substituted olefins by deoxystannylation through a tin-Peterson reaction. [7][8][9][10] Heteroatom compounds bearing silicon and tin on the same -carbon were subjected to selective electrochemical oxidation, using silicon and tin as electroauxiliaries, 11 and then reacted with nucleophiles, showing the versatility of this kind of polyfunctionalized molecules.…”

Sugar Allyltin Compounds: Preparation and Application in Organic Synthesis

“…Thomas studied the reactions between such substituted allyltin derivatives and aldehydes in a series of papers, and found that the attack of electrophile in the SnCl 4 -catalyzed process occurred exclusively at the α-carbon atom. [60] The formation of such products may be explained in terms of transmetallation of 24 with SnCl 4 to afford 27 (an X-ray structure of such a type of oxastannane has been described in the literature [61] ), which upon treatment with aldehyde gives compound 26 (Scheme 3). When boron trifluoride was used 1,4-elimination was observed and the yields of the desired coupling products were low.…”