Stereodivergent addition of 4-Silyloxy-1,2-Allenes to aldehydes by hydroboration

Abstract

We have established a new stereodivergent approach to 2-vinyl-1,3-diols based on a hydroboration of allene/addition of aldehyde tandem process. The stereocenter present next to the allenyl moiety (C1) in the starting allene effectively determines the configuration of the new formed carbinol (C3) whereas the relative configuration of C2 and C3 is determined by the configuration (E/Z) of the transient 2- alkenylborane intermediate. It should be noted that the order of mixing of the reagents and the kind of aldehyde used allowed us to obtain three out of the four possible diastereomers of the 1,3- diol.