Diastereoselective addition of alkynylalanes to carbohydrate-derived nitrones

Catalytic Enantioselective Alkyne Addition to Nitrones Enabled by Tunable Axially Chiral Imidazole-Based P,N-Ligands

Although catalytic enantioselective alkyne addition is an established method for the synthesis of chiral propargylic alcohols and amines, addition to nitrones presents unique challenges, and no general chiral catalyst system has been developed. In this manuscript, we report the first Cu-catalyzed enantioselective alkyne addition to nitrones utilizing tunable axially chiral imidazole-based P,N-ligands. Our approach effectively overcomes difficulties in both reactivity and selectivity, resulting in a simple Cu-catalyzed protocol. The reaction accommodates a wide range of nitrones and alkynes, enabling the streamlined synthesis of chiral propargyl N-hydroxylamines via the enantioselective C-C bond formation. A diverse array of optically active nitrogen-containing compounds, including chiral hydroxylamines, can be accessed directly through facile transformations of the reaction products.

Synthesis of Pyrrolidine Monocyclic Analogues of Pochonicine and Its Stereoisomers: Pursuit ofSimplified Structures and Potent β-N-Acetylhexosaminidase Inhibition

Ten pairs of pyrrolidine analogues of pochonicine and its stereoisomers have been synthesized from four enantiomeric pairs of polyhydroxylated cyclic nitrones. Among the ten N-acetylamino pyrrolidine analogues, only compounds with 2,5-dideoxy-2,5-imino-d-mannitol (DMDP) and pochonicine (1) configurations showed potent inhibition of β-N-acetylhexosaminidases (β-HexNAcases); while 1-amino analogues lost almost all their inhibitions towards the tested enzymes. The assay results reveal the importance of the N-acetylamino group and the possible right configurations of pyrrolidine ring required for this type of inhibitors.

First total synthesis of (+)-broussonetine W: glycosidase inhibition of natural product & analogs

Broussonetine W and its 11 analogues have been first synthesized from cyclic nitrones and assayed as potential gycosidase inhibitors.

Diastereoselective synthesis of propargylic N-hydroxylamines via NHC–copper(i) halide-catalyzed reaction of terminal alkynes with chiral nitrones on water

The first NHC–copper(i) halide catalyzed addition of terminal alkynes to enantiomerically pure nitrones on water affording propargylic N-hydroxylamines in a highly diastereoselective fashion is reported.

N-[(Z)-4-Methoxybenzylidene](methoxycarbonyl)methanamine oxide

The title compound, C₁₁H₁₃NO₄, contains a nitrone group, C=N—O—R, the geometry of which shows a Z configuration with near planarity (r.m.s. deviation = 0.0787 Å) around the C=N double bond. An intra­molecular C—H⋯O hydrogen bond generates an S(6) ring motif. In the crystal packing, mol­ecules are linked into R₂²(12) dimers and R₂²(14) rings via C—H⋯O inter­molecular hydrogen bonds.