Organic Chemistry

Regioselective anti-Silyllithiation of Propargylic Alcohols



Among the known hydrosilylation or carbosilylation conditions of alkynes, anti-addition of the two units across the triple bond is considered rare compared to the syn counterpart. For anti-silylative vicinal difunctionalizations, transition-metal catalysts, such as ruthenium or palladium complexes, are generally required. Accordingly, silyl alkali metals have not been employed for those anti-addition transformations. Here we demonstrate that silyllithiums can add across the triple bond of a series of propargylic alkoxides regioselectively in an anti-fashion. Upon treatment with a variety of electrophiles, the tri-substituted alkenyl lithium intermediates were transformed into highly functionalized β-silyl allylic alcohols with high regio-control, eventually providing tri- or tetrasubstituted alkenylsilanes stereoselectively. A classic trick for anti-addition with propargylic alkoxides has transformed anti-silylative functionalizations into a robust and reliable strategy.

Version notes

Slight changes in the main text from version 3 (not version 4) and the manuscript template. Changes in the order of the compounds in SI and several corrections of spectra.


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Supplementary material

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Supporting Information
Experimental procedures, characterization and spectral data for new compounds