화학공학소재연구정보센터
Journal of the American Chemical Society, Vol.138, No.37, 12061-12064, 2016
Stereoselective Domino Carbocyclizations of gamma- and delta-Cyano-N-tosylhydrazones with Alkenylboronic Acids with Formation of Two Different C(sp(3))-C(sp(2)) Bonds on a Quaternary Stereocenter
A novel strategy for the synthesis of functionalized carbocycles is defined, through the cascade carbocylization of alkenylboronic acids with delta- or gamma-cyano-N-tosylhydrazones. In the reaction, two C(sp(3))-C(sp(2)) bonds are formed on the former hydrazonic carbon generating an all-carbon quaternary stereocenter, and leading to cyclic ketones featuring an alkenyl side chain with complete diastereoselectivity. The processes are conducted under very simple experimental conditions, only in the presence of K2CO3, in 1,4-dioxane as solvent and under microwave irradiation, and have been applied for the synthesis of a wide structural variety of fused cyclopentanones and cydohexanones. Moreover, the versatility of this methodology has been demonstrated in the structural modification of androsterone.