Tert-butyl radicals have many hydrogens on adjacent carbons to donate and steric effects often prevent tert-butyl radicals from getting close to abstracting hydrogens.

In the first step, borane (BH) adds to the double bond, transferring one hydrogen from itself to the adjacent carbon.

From a synthetic point of view, the most challenging structural features of the molecule are the C3 spirocyclic ring juncture and the adjacent prenyl-substituted carbon.

It resembles a benzene ring, except that two adjacent carbons are replaced by nitrogen and boron, respectively.

Has the lowest-numbered locants for multiple bonds (The locant of a multiple bond is the number of the adjacent carbon with a lower number).

The p-orbital at fluorine parallel to the one on the adjacent carbon will face an optimal interaction.

Next is a concerted migration of one of the adjacent carbons to oxygen with loss of a carboxylic acid.

In this reaction, sulfur is reduced while adjacent carbon is oxidized.

What follows is a 1,2-rearrangement when an alkyl substituent on the anionic boron migrates to the adjacent electrophilic carbon of the carbonyl group.

Subsequently, an alkyl group from the adjacent carbon migrates to the carbocation center.