lithium aluminium tetrahydride in diethyl ether T=0°C; 1 h;

1.1: n-BuLi / tetrahydrofuran 1.2: SiCl4 / tetrahydrofuran / -78 - 20 °C 2.1: LiAlH4 / diethyl ether / 1 h / 0 °C View Scheme

in benzene-d6 all manipulations under dry Ar atm.; equimolar amt. of B compd. added tosoln. of Si compd. in one portion at room temp., kept for several h at room temp.; monitored by (1)H and (29)Si NMR spectra; distribution of 1,1- and 1,2-allylborated products 5:95;