An Easy Preparation of α-Allenic Ethers and Tertiary α-Allenic Amines

Facile Synthesis of Bicyclic and Tricyclic Skeletons by Cycloisomerizations of Hept-1-en-6-ynes and 4,9-Diheteradodeca-1,11-dien-6-ynes, Followed by [4 + 2] Cycloadditions

“…Ϫ All chemicals were used as commercially available, unless otherwise noted. The substances 3-tert-butyldimethylsilyloxy-1-propyne (2), [22] 2,2-dimethylpent-4-enal (3), [23] N-allyl-p-toluenesulfonamide (20), [24] N-allyl-N-benzylamine (25), [25] 1,4-dibromobut-2-yne (26), [26] but-2-yne-1,4-diamine (29), [27] 1-(allyloxy)-4-bromobut-2-yne (42) [28] and 1,4-bis(allyloxy)but-2-yne (36) [20] were prepared according to literature procedures.…”

“…While the dienyl diether 36, prepared as reported by Barbot et al, [20] cyclized under the same catalytic system conditions as used with 27, giving the corresponding dioxatricy- cle 37 in 80% yield, all attempts to tricyclize the acyclic diacrylate 33 yielded only oligomeric material. It is not certain whether the precursor diacrylate or the monocyclic intermediate underwent polymerization.…”

“…For example, 1,4-dibromobut-2-yne (26) could be aminated twice with N-allyl-N-tosylamine (20) to give N,NЈ-diallyl-N,NЈ-ditosylbut-2-yne-1,4-diamine (27) in 90% yield Scheme 7. Syntheses of nitrogen-containing dodeca-1,11-dien-6-ynes; A: NaH, THF, 0°C; B: Et 2 O, 0°C (Scheme 7).…”

Site-Selective [2+2+n] Cycloadditions for Rapid, Scalable Access to Alkynylated Polycyclic Aromatic Hydrocarbons

“…[Ir(COD)Cl]2 was either purchased from Strem chemical or prepared according to the literature. 1 2,4-Dibromo-1,5-diiodobenzene (S1), 2 2,5-dibromo-1,4diiodobenzene (S2), 3 3,6-dibromo-2,7-diiodo-9,10-dimethoxyphenanthrene (S4), 4 3,6-dibromo-2,7-bis(pent-1-ynyl)-9,10-dimethoxyphenanthrene (S7), 4 EtCMo(OC(CH3)(CF3)2)3(DME) (Mo-2), 5 PdCl2(IPr)(3-chloropyridine), 6 i PrMgCl•LiCl, 7 Ir(COD)(dppe)Cl, 8 1,4-bis(hexyloxy)but-2-yne, 9 1,4-dimethoxy-2-butyne, 10 2,2',4,4'-tetra(prop-1-yn-1-yl)-5,5'-dibromobiphenyl (1b), 11 and 1,5dibromo-2,4-di(prop-1-yn-1-yl)benzene (4b) 11 were prepared by literature procedures or slight modifications thereof. Solutions of ZnCl2 and CuCN•2LiCl in THF were prepared as follows.…”

Nickel-Catalyzed Highly Regio- and Stereoselective Cross-Trimerization between Triisopropylsilylacetylene and Internal Alkynes Leading to 1,3-Diene-5-ynes

“…Toluene was distilled over Na/benzophenone prior to use. Ni(cod) 2 , bis(methoxymethyl)acetylene (2d), 2 bis(ethoxymethyl)acetylene (2e), 3 bis(propoxymethyl)acetylene (2f), 3 bis(methoxymethoxymethyl)acetylene (2g), 4 3-ethoxy-1-propynylbenzene (2h), 5 3-methoxymethyl-1-propynylbenzene (2k), 6 Benzylazide, 7 and ferrocenylmethylazide 8 were prepared according to the literature methods. Other known reagents employed in this research were commercially available and used without further purification.…”