26 research outputs found
Organocatalytic Visible Light Enabled S<sub>N</sub>Ar of Heterocyclic Thiols: A Metal-Free Approach to 2‑Aminobenzoxazoles and 4‑Aminoquinazolines
The
direct amination reaction of heterocyclic thiols has been developed
in the presence of the nonhazardous photocatalyst Rose Bengal under
irradiation of visible light. The reaction provides a straightforward
approach to pharmaceutically and synthetically useful 2-aminobenzoxazole
and 4-aminoquinazoline derivatives from the corresponding heterocyclic
thiols with amines in good to excellent yields. Our photochemical
reaction can be successfully adapted into a continuous flow reactor
which is applicable for large-scale chemical industry. The key benefits
of this reaction include the use of metal-free, low-cost Rose Bengal
catalyst and practical operation (ambient temperature, open flask,
and undried solvents)
Synthesis of Phosphaguanidines by Hydrophosphination of Carbodiimides with Phosphine Boranes
The direct addition of anionic secondary
phosphine boranes to carbodiimides
yields both chiral and achiral phosphaguanidine boranes under ambient
temperature conditions. An analogous preparation of menthol-derived
phosphinite boranes is also described. These products can be deborinated
to give the corresponding phosphines, and subsequently oxidized to
give phosphine oxides. The robustness of this method was further demonstrated
in the synthesis of structurally novel cyclic phosphaguanidines
Synthesis of Phosphaguanidines by Hydrophosphination of Carbodiimides with Phosphine Boranes
The direct addition of anionic secondary
phosphine boranes to carbodiimides
yields both chiral and achiral phosphaguanidine boranes under ambient
temperature conditions. An analogous preparation of menthol-derived
phosphinite boranes is also described. These products can be deborinated
to give the corresponding phosphines, and subsequently oxidized to
give phosphine oxides. The robustness of this method was further demonstrated
in the synthesis of structurally novel cyclic phosphaguanidines