Reaction of cyclic secondary amines with 1-alkynes and copper(I) chloride at 110-120 °C gives the corresponding alkynylcopper complex, which adds to the iminium ion intermediate formed in situ by hydroamination of 1-alkynes to give the corresponding propargylamine derivatives in up to 94% yield and 99% regioselectivity. The diastereomerically pure chiral propargylamines were obtained in 23-89% yield using optically active 2-benzyl morpholine and N-methyl camphanyl piperazine. These chiral propargylamines are readily converted to the corresponding trisubstitued chiral allenes in 71-89% yields with up to 99% ee upon reaction with ZnBr2 at 120 °C. The results are discussed considering mechanisms involving diastereoselective addition of alkynylcopper complex formed in situ to iminium ions formed in situ regioselectively to produce the corresponding propargylamines, which in turn give the chiral allenes with very high enantioselectivity via an intramolecular 1,5-hydrogen shift in the presence of zinc bromide.

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Synthesis and characterization of thermo-sensitive block copolymer of N-isopropyl acryl amide-b-Alanine [(NIPAM)-b-(Alanine)] thin film and its doping with (AuNPs)-(SiO 2 NPs), (gold and silica nanoparticles) were reported. Further, composite effect on K562 (leukemia) cells was examined based on in vitro cell-based studies. The synthesis of SiO 2 NPs was followed through facile Stober's sol-gel synthesis methods. The individual morphology of [(NIPAM)-b-(Alanine)] thin film, AuNPs and SiO 2 NPs including [(NIPAM)-b-(Alanine)]@(Au)-(SiO 2 NPs) composite was confirmed by using TEM instrumentation. [(NIPAM)-b-(Alanine)] thin film was embedded with gold and silica nanoparticles followed by the sonication. The average size of AuNPs is 16 nm and for SiO 2 NPs, it is ∼368 nm (in diameter). Synthesized composite [(NIPAM)-b-(Alanine)]@(Au)@(SiO 2 NPs) is biocompatible for mankind use. However, composite used to examine the inhibitory activity on K562 cells and it shows ∼78% inhibition, which is significant value for 24 h treatment under humidified atmospheric conditions.

Diphenylphosphinoethane (DPPE)-catalyzed and ZnI-promoted in situ formation of oxazolidine, alkynyl zinc, and propargylamine intermediates from 1-alkynes, chiral (S)-diphenyl(pyrrolidin-2-yl)methanol, and propiolates gave the corresponding chiral (R)-β-allenoates in 40-72% yield with up to >99% ee. The intermediate propargylamine was isolated in 50% yield and converted to give the β-allenoate 10aa in 68% yield and 96% ee upon reaction with ZnI. The results are discussed considering a mechanism involving oxazolidine and iminium ions formed in situ followed by addition of alkynyl zinc complex to produce the propargylamine that gives the corresponding allenoate via a 1,5-hydrogen shift in the presence of ZnI.

Propargylamines are significant building blocks for the generation of polyfunctional amino analogues, natural products, and pharmacologically active drugs. Herein we report the most straightforward approach is to use 1,10‐phenanthroline copper(I) complexes as a catalyst to promote the (Alkyne‐Alkyne‐Amine) A3 coupling reaction between cyclic secondary amines and two terminal alkynes that generates a ketimine intermediate in situ through hydroamination, which subsequently interacts with the alkenyl copper complex to produce tetrasubstituted propargylamine. In the addition of zinc halide, the propargylamines converted into trisubstituted allenes with up to 90% yield. When Sc(OTf)3 is used to perform the [4+2] cycloaddition reaction with enophile (alkene), the cyclized product obtained in up to 72% yield. On the other hand, the allene was subjected to a metal‐free intermolecular cyclization reaction to produce the highly substituted pyridine derivative, although this provides only up to 30% yield.