Stereoselective Syntheses of Oxetanes

However, this model can also be generalized to other cydicalkenes. The ISC reactive conformation of the intermediary triplet biradicals is important for stereoselectivity, as the rate constant for ISC, which is controlled by a spin-orbit-coupling (SOC) mechanism, is heavily dependent on the orientation of the two spin centers. The importance of the ISC process was reasonably proved by the low mdo-sclcctivity in PB reactions with naphthaldehydes or aliphatic aldehydes, in which the excited singlet states may react with alkenes [34]. The stereoselectivity observed in the PB 

Zamojski, Scharf, and Bach and colleagues have shown the PB reaction to be applicable for the asymmetric synthesis of oxetanes. In 1982, Zamojski and 

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