Thionolactone ruthenium complexes

In 1994, the atropodiastereoselective ring opening of chiral thionolactone-ruthenium complexes prepared according to Scheme 5.18 was investigated by Bringmann et al ... 

However, an achiral ruthenium fragment in combination with a chiral hydride source could also be involved. Thus, atropoenantioselective ring cleavage of achiral thionolactone-ruthenium complexes with chiral H-nucleo-philes, such as BINAL-H, provided the corresponding thioether in quantitative yield and excellent enantioselectivity (Scheme 5.20)." ... 

Achiral ruthenium fragments can also be used with a chiral reductant. The reduction of a [CpRu(DPPE)(thionolactone)] complex with BINAL-H and decomplexa-tion as above gave the thioether in 84 % ee [53],... 

The two-fold hydride addition to biaryl-thionolactone complexes followed by decomplexation of the generated ruthenium thiolates yielded the... 

---