NEW FORMULAS FOR ORGANOZINCATE CHEMISTRY

As a new type of zincate, we designed various new organozinc derivativ es, Me3Zn(R)Li-2 (R = Me, CN, SCN), which could be prepared in situ fr om lithium trimethylzincate and anion species such as methyllithium, l ithium cyanide, and lithium thiocyanate. We investigated the reactivit ies of these zincates toward the halogen (or tellurium)-zinc exchange, Michael addition, carbozincation, and epoxide ring opening reactions. On the basis of their excellent chemical yields and chemoselectivitie s, these species were considered to be differentiated from ordinary tr iorganozincates, R3ZnLi. We also discuss the structure of the newly de signed zincates using H-1 NMR/Raman/in situ FTIR-extended X-ray absorp tion fine structure (EXAFS) spectroscopic and the density-functional t heory (DFT) theoretical studies. All results strongly support the fact that these newly designed zincates are a new category of zincate spec ies. This observation is also identical with the fact that newly desig ned zincates have a higher and unique reactivity compared to the conve ntional triorganozincates.