2- methoxy carbonyl- 1-methyl-, formylation

Another possible reason that ethylene glycol is not produced by this system could be that the hydroxymethyl complex of (51) and (52) may undergo preferential reductive elimination to methanol, (52), rather than CO insertion, (51). However, CO insertion appears to take place in the formation of methyl formate, (53), where a similar insertion-reductive elimination branch appears to be involved. Insertion of CO should be much more favorable for the hydroxymethyl complex than for the methoxy complex (67, 83). Further, ruthenium carbonyl complexes are known to hydro-formylate olefins under conditions similar to those used in these CO hydrogenation reactions (183, 184). Based on the studies of equilibrium (46) previously described, a mononuclear catalyst and ruthenium hydride alkyl intermediate analogous to the hydroxymethyl complex of (51) seem probable. In such reactions, hydroformylation is achieved by CO insertion, and olefin hydrogenation is the result of competitive reductive elimination. The results reported for these reactions show that olefin hydroformylation predominates over hydrogenation, indicating that the CO insertion process of (51) should be quite competitive with the reductive elimination reaction of (52). 

Acyclic 295 and cyclic 296 hemithioacetals have been shown as precursors of formyl-lithium intermediates13. For the preparation of the starting methoxy(phenylsulfanyl) methane 295466 two main procedures can be used (a) nucleophilic substitution of chloro-methyl methyl ether with thiophenol under basic conditions467,468 and (b) boron trifluoride etherate-catalyzed condensation of thiophenol and dimethoxymethane166. 1,3-Oxathiane and its derivatives can be prepared by acetalization of the corresponding carbonyl compound with 3-mercaptopropanol. 

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