1. Brookhart's mechanistic studies show that the concentration of the alkyl-ethylene palladium complex required to give double ethylene insertions is very low at any one point: Additionally, the Gibbs energy of activation of the alkyl-ethylene insertion is ~ 3 kcal/mol higher than the corresponding activation barrier for the alkyl-carbon monoxide insertion.

Brookhrt의 기계론적 연구는, 에틸렌을 두 번 삽입하기 위해 필요한 알킬에틸렌 팔라듐 중합체의 농축은 항상 낮다는 것을 보여준다.: 또한 알킬에틸렌 삽입의 활성화깁스에너지는 알킬-일산화탄소 삽입의 활성화장벽(활성화깁스에너지)보다 3kcal/mol 더 높다.