Catalytic Asymmetric Synthesis of Diketopiperazines by Intramolecular Tsuji–Trost Allylation
作者:Matteo Faltracco、Silvia Cotogno、Christophe M. L. Vande Velde、Eelco Ruijter
DOI:10.1021/acs.joc.9b01994
日期:2019.9.20
We report the intramolecular Tsuji–Trost reaction of Ugi adducts to give spiro-diketopiperazines in high yield and with high enantioselectivity. This approach allows the catalyticasymmetric construction of a broad range of these medicinally important heterocycles under mild conditions, in two steps from cheap, commercially available starting materials.
Pd-catalyzed regio- and enantioselectiveallylicsubstitution of hydroxyl-containing allylic carbonates with 2-pyridones has been developed. By using a palladium complex in situ generated from Pd2(dba)3·CHCl3 and phosphoramidite L2 as a ligand, the process allowed rapid access to N-substituted 2-pyridones with complete chemo- and regioselectivities and good to high enantioselectivities.
An intramolecular umpolung allylation of imines is reported. This reaction occurs via the intermediacy of 2-azaallyl anions. It could proceed either under transition-metal-catalyzed conditions or under transition-metal-free conditions. Importantly, this approach afforded trans-3-vinyl-4-aminochromanes with high diastereoselectivity, while conventional, nonumpolung methods often display high cis-selectivity