SYNTHESIS OF HEAVIER ANALOGUES OF ALKENES, R₂E=CR`₂ (E= Si, Ge, Sn) VIA LITHIUM SILANOLATE ELIMINATION

The synthesis of compounds with multiple bonds between heavy 14 elements is a challenge because of their high reactivity, e.g, dimerization. There are several methods for the synthesis of R₂E=CR’₂ (E= Si, Ge, Sn).¹ Our group developed the Peterson-type elimination method (via lithium silanolate elimination) for the synthesis of such compounds.² Using this method we successfully synthesized several stable silenes and a transient germene.³

Now we report the synthesis of (t-BuMe₂Si)₂E=Ad-2 (E = Si, Ge, Sn) and their trapping with para-quinone. In the first step of the synthesis ECl₄ reacts with four equivalents of t-BuMe₂SiLi to give tri-silyl-substituted lithium anion 1 (Scheme, step a). Then the reaction of 1 with 2-adamantanone leads to formation of the desired product 2 via lithium silanolate elimination (Scheme, step b). Using this method we successfully synthesized silene 2a, germene 2b and stannene 2c. 2a-c were trapped by reaction with para-quinone 3 (Scheme, step c). The obtained products 2a-c and 4a-c were characterized by X-ray crystallography and NMR spectroscopy. The reactivity of 2a-c and theoretical study of 2c are under current investigation.

References:

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