Oxirane opening reaction with lithiated

On the contrary, a-lithiated epoxides have found wide application in syntheses . The existence of this type of intermediate as well as its carbenoid character became obvious from a transannular reaction of cyclooctene oxide 89 observed by Cope and coworkers. Thus, deuterium-labeling studies revealed that the lithiated epoxide 90 is formed upon treatment of the oxirane 89 with bases like lithium diethylamide. Then, a transannular C—H insertion occurs and the bicyclic carbinol 92 forms after protonation (equation 51). This result can be interpreted as a C—H insertion reaction of the lithium carbenoid 90 itself. On the other hand, this transformation could proceed via the a-alkoxy carbene 91. In both cases, the release of strain due to the opening of the oxirane ring is a significant driving force of the reaction. 

Synthesis of Vinylsilanes. Lithiated reagent (2) reacts with a-trimethylsilyloxiranes to yield vinylsilanes (eq 8). The reaction involves nucleophilic opening of the oxirane ring by (2), followed by 1,2-elimination of a silyl and a phenylthio group. ... 

---