In the mechanism of hydroboration-oxidation of an alkene, how many atoms are directly involved in th — Reaction Mechanism Chemistry Question

💡 Solution & Explanation

The initial step of hydroboration is a concerted, stereospecific syn-addition. The boron atom and one of its hydrogen atoms add simultaneously across the two carbon atoms of the alkene's $\pi$ -bond. This simultaneous breaking and making of bonds occurs through a cyclic, four-membered transition state involving two carbon atoms, one boron atom, and one hydrogen atom.