Bis(oxazoline) Lewis Acid Catalyzed Aldol Reactions of PyridineN-Oxide Aldehydes—Synthesis of Optically Active 2-(1-Hydroxyalkyl)pyridine Derivatives: Development, Scope, and Total Synthesis of an Indolizine Alkaloid
A new, short, and simplified procedure for the synthesis of optically active pyridine derivatives from pro-chiral pyridine-N-oxides is presented. The catalytic and asymmetric Mukaiyama aldol reaction between ketene silyl acetals and 1-oxypyridine-2-carbaldehyde derivatives catalyzed by chiral copper(II)-bis(oxazoline) complexes gave optically active 2-(hydroxyalkyl)- and 2-(anti-1,2-dihydroxyalkyl)pyridine
A general catalytic oxo-hetero-Diels−Alder reaction for pro-chiral aldehyde and ketone N-oxy-pyridines is presented. The catalytic and asymmetric oxo-hetero-Diels−Alder reaction of electron-rich dienes with N-oxy-pyridine-2-carbaldehyde and ketone derivatives, catalyzed by chiralcopper(II)−bisoxazoline complexes, gives optically active six-membered oxygen heterocycles in moderate to good yields and
Asymmetric Synthesis of Adjacent Tri‐ and Tetrasubstituted Carbon Stereocenters: Organocatalytic Aldol Reaction of an Hydantoin Surrogate with Azaarene 2‐Carbaldehydes
作者:June Izquierdo、Noémie Demurget、Aitor Landa、Tore Brinck、Jose M. Mercero、Peter Dinér、Mikel Oiarbide、Claudio Palomo
DOI:10.1002/chem.201902817
日期:2019.9.20
A bifunctional amine/squaramide catalyst promoted direct aldol addition of an hydantoin surrogate to pyridine 2-carbaldehyde N-oxides to afford adducts bearing two vicinal tertiary/quaternary carbons in high diastereo- and enantioselectivity (d.r. up to >20:1; ee up to 98 %) is reported. Acid hydrolysis of adducts followed by reduction of the N-oxide group yields enantiopure carbinol-tethered quaternary
The present invention relates novel heterocyclic analogs of combretastatin, their synthesis, and their use as anti-cancer compounds. In particular, compounds of Formula (I), Formula (II), and Formula (V) are provided.
The present invention relates novel heterocyclic analogs of combretastatin, their synthesis, and their use as anti-cancer compounds. In particular, compounds of Formula (I), Formula (II), and Formula (V) are provided.