低价钛引起的(3-氧代-1,3-二芳基)丙基丙二腈的还原环化反应

报道了低价钛试剂(TiCl-Zn体系)与(3-氧代-1,3-二芳基)丙基丙二腈的反应.研究发现,低价钛可引起(3-氧代-1,3-二芳基)丙基丙二腈的成环反应,生成2-氰基-3,5-二芳基-1-氨基环戊烯、反式和顺式2-氨基-3-氰基-1,4-二芳基-2-环戊烯-1-醇3种产物,并用X射线衍射法确定了后两种异构体的构型.

Low-valent Titanium Induced Reductive Cyclization of (3-Oxo-1,3-diaryl)propylpropanedinitrile

This paper reports the reactions of low-valent titanium reagent(TiCl₄-Zn system) with (3-oxo-1,3-diaryl) propylpropanedinitrile. It is found that the low-valent titanium can promote a novel cyclization of (3-oxo-1,3-diaryl)propylpropanedinitrile to give 2-cyano-3,5-diary-1-aminocyclopentene, trans and cis 2-amino-3-cyano-1,4-diary-2-cyclopentene-1-ol. The latter's configurations are determinated by X-ray diffraction analysis.The crystal of compound 3c is triclinic with space group P1, a =1.0389(4) nm, b =1.2292(4) nm, c = 0.8027(3) nm, 7 α = 93.29(3)°, r =113.32(3)°, V =0.9362(6) nm³, Z =2, D_c=1.1939 g/cm³, μ =0.77 cm^-1, F (000)= 360, and find R =0.067 and R_w=0.057 for 1308 reflections ( I >3 σ ( I )). The crystal of compound 4a is orthorhombic with space group Pbcn, a = 1.3370(5) nm, b = 1.0481(5) nm, c =2.3350(6) nm, V =3.272(3) nm³, Z =8, D_c= 1.262 g/cm³, μ = 2.36 cm^-1, F (000)=1296, and find R =0.043 and R_w=0.049 for 1426 reflections ( I >3 σ ( I )). A possible reaction mechanism is proposed in this paper.