Synthesis of 5‐Halo‐4H‐1,3‐oxazine‐6‐amines by a Copper‐Mediated Domino Reaction

Gold-Catalyzed Cyclizations of Alkynol-Based Compounds: Synthesis of Natural Products and Derivatives

“…Thus, it has been recently established a general method for the synthesis of highly functionalized isoxazoles from alkynyl oxime ethers [ 80 ], or an intermolecular alkyne oxidation leading to 2,5-disubstituted oxazoles [ 81 ]. Nevertheless, while gold-based alkyne-oxygen cycloisomerization has recently become a hot topic in organic synthesis, only a few examples for alkyne-nitrogen coupling have been described [ 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 ]. Regarding the synthesis of natural products and derivatives, Chan et al have recently described the synthesis of highly substituted indole skeletons [ 29 ], from readily available 2-tosylamino-phenylprop-1-yn-3-ols 38 [ 91 ].…”

Heterocyclic chemistry

“…Hashmi et al reported a copper(II)-mediated domino reaction with 6-endo-ring closure, and reductive elimination to introduce the 5-halogen substituent. 76 Ye and co-workers reported a one-pot tandem reaction catalyzed by a chiral secondary amine to give optically active derivatives of the fused 1,3-oxazine system. 77 Seven-membered rings and higher Kundu and co-workers reported the synthesis of iodo-indoloazepinones in a threecomponent domino reaction via a regioselective 7-endo-dig iodo-cyclization pathway (Scheme 43).…”

A Highly Stereoselective Addition of Lithiated Ynamides to Ellman–Davis Chiral N-tert-Butanesulfinyl Imines

“…To continue developing useful methods for constructing N- heterocycles, we have been exploring N- tethered intramolecular transformations through usage of γ-amino-ynamides such as 1 [Scheme ] . We recognized that the Cu-catalyzed protocol ,, may actually not be the most attractive approach because it would require (a) optically enriched propargyl amines 3 , which are not always readily available, and (b) a deprotection protocol that may not be compatible with ynamides 2 in addition to being tedious . Yet, with N- protected propargyl amines 5 , the most direct access would be an addition of metalated chiral ynamide 4* to achiral imines 5 , which would constitute a long-range stereochemical induction.…”