Organolithium reagents oxirane reactivity

Reactivity of oxiranes with organolithium reagents TABLE 9. Kinetic resolution of racemic oxiranes using HCLA 53... 

The reactivity of oxiranes with organolithium reagents, including deprotonation, ring cleavage, and the preparation and reactivity of lithiooxiranes, has been reviewed by Chemla and Vrancken . 

Derivatives of azete are only known as unstable reaction intermediates. Oxetane and azetidine are considerably less reactive than their three-membered connterparts (oxetane reacts with hydroxide anion 10 times more slowly than does oxirane), but nonetheless do undergo similar ring-opening reactions, for example oxetane reacts with organolithium reagents in the presence of boron triflnoride, or with cuprates, and azetidine is opened on heating with concentrated hydrochloric acid. Azetidininm ions react mnch more easily with nucleophiles. ... 

Although oxirane (oxacyclopropane) and oxetane (oxacyclobutane) react with Grignard and organolithium reagents to form alcohols, tetrahydrofuran (oxacyclopentane) is so unreactive that it can be used as the solvent in which these organometallic compounds are prepared. Explain the difference in reactivity of these oxygen heterocycles. 

The use of a catalytic amount of the homochiral ligand is here allowed by the poor reactivity of aryllithium reagents toward oxiranes, the reaction being supposed to occur through the more reactive organolithium/Schiff base complex 109, as depicted in Scheme 49. 

Organolithium compounds are less reactive than lithium organocuprates. A number of publications deal with the differences observed between the two reagents in the ring-opening reaction of oxiranes. The reaction of 1,3-cyclohexadienemonooxirane with methyllithium is seen in Eq. 277. ... 

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