 But by installing the a bulky TMS substituent, the reaction gave the desired product in high diastereoselectivity and regioselectivity in good yield.The bulky TMS substituent helps enhance allylic 1,3 strain in the conformation of the molecule.In the seminar paper on the total synthesis of (+)-monensin, Kishi and co-workers utilized the allylic strain to induce asymmetric induction in the hydroboration oxidation reaction.