An efficient synthetic method for preparing enantioenriched secondary borylalkanes has been achieved through a copper-catalyzed regio- and enantioselective hydroallylation of alkenyl boronates and boramides employing hydrosilanes and allylic phosphates. In the presence of a copper catalyst with a chiral Walphos ligand, a range of alkenylboron compounds with an aryl, heteroaryl, or alkyl substituent produced secondary homoallylic alkylboron compounds in good yields and with high enantioselectivities up to 99% ee. The utility of the resulting alkylboronates was demonstrated in an efficient synthesis of (S)-massoialactone.
Bibliographical noteFunding Information:
This research was supported by National Research Foundation of Korea (NRF) grants (NRF-2016R1A2B4011719 and NRF-2016R1A4A1011451), funded by the Korea government (MEST).
© 2016 American Chemical Society.