trans-Hydroboration–oxidation products in Δ5-steroids via a hydroboration-retro-hydroboration mechanism by Hilario-Martínez, JC, Murillo, F, García-Méndez, J, Dzib, E, Sandoval-Ramírez, J, Muñoz-Hernández, MÁ, Bernès, S, Kürti, L, Duarte Gonzalez, FJ, Merino, G, Fernández-Herrera, MA