In this work we used DFT B3LYP/6-311+G** to study the mechanism and the regio- and stereoselectivity of the [1+2] cycloaddition reaction between α-cis-himachalene and dibromocarbene. We found that the reaction follows a concerted asynchronous mechanism and is exothermic and stereoselective. Treatment of α-cis-himachalene with one equivalent of dibromocarbene leads to the formation of two products resulting from attack of the most substituted double bond of α-cis-himachalene. Treatment of α-cis-himachalene with two equivalents of dibromocarbene leads to formation of two products resulting from attack of the exocyclic double bond.
