Two regioselective, high-yield routes-to nido-6-alkyldecaborane(14)s via one-pot syntheses are reported. Alkyllithium reagents add to salts of nido-B10H13- to form arachno-6-R-B10H132-, which may be protonated using HCl/Et2O, first to the corresponding arachno-6-R-B10H14- anion and then, with H-2 loss, to nido-6-R-B10H13. Alternately, olefin hydroboration of arachno-6,9-(SMe2)(2)-B10H12 produces nido-6-R-8-(SMe2)-B10H11, which may be reduced, using Superhydrid, to nido-6-R-B10H12-, and then protonated with HCl/Et2O to nido-6-R-B10H13. X-ray diffraction studies of the following intermediates and products are presented : nido-8-(SMe2)-B10H12, nido-6-Thx-8-(SMe2)-B10H11, and nido-6-Thx-B10H13.