125641-97-6Relevant academic research and scientific papers
A Facile Preparation of Alkenyl- and Allenylmetallic Compounds by Means of Iodine-Metal Exchange and Their Use in Organic Synthesis
Shinokubo, Hiroshi,Miki, Hiroaki,Yokoo, Toshiaki,Oshima, Koichiro,Utimoto, Kiitiro
, p. 11681 - 11692 (1995)
Stereospecific lithium-halogen exchange of alkenyl iodides was performed upon treatment with butyllithium in non-polar solvents such as hexane, benzene, and toluene at 25 deg C to provide alkenylllithiums quantitatively with retention of the configuration.Metal-iodine ecxhange of allenyl iodides with n-BuLi, i-PrMgBr or Et2Zn was also performed effectively to afford the corresponding allenylmetallic reagents.An addition of carbonyl compounds to the metallic reagents gave homopropargylic alcohols with high regioselectivity in good yields.
Reactions between Tantalum- or Niobium-Alkyne Complexes and Carbonyl Compounds
Kataoka, Yasutaka,Miyai, Jiro,Oshima, Koichiro,Takai, Kazuhiko,Utimoto, Kiitiro
, p. 1973 - 1981 (2007/10/02)
A variety of tantalum-alkyne complexes are generated in situ by treatment of alkynes with low-valent tantalum derived from TaCl5 and zinc.These complexes add regioselectively to carbonyl compounds in a one-to-one fashion to yield (E)-allylic alcohols stereoselectively.Iodinolysis of the oxatantalacyclopentene, which is postulated as an intermediate of the reaction, gives a (Z)-3-iodo-2-propen-1-ol derivative.In contrast to tantalum-alkyne complexes, niobium-alkyne complexes, prepared with low-valent niobium derived from NbCl5 and zinc, add in situ to aldehydes in a one-to-two fashion to give 1,3-diene derivatives.The dienes are produced through (i) addition of the alkyne complexes with 2 equiv of aldehydes at cis vicinal positions of the alkenes and (ii) deoxygenative elimination of 2,7-dioxanioba-4-cycloheptene complexes.
Tantalum-Alkyne Complexes as Synthetic Intermediates. Stereoselective Preparation of Trisubstituted Allylic Alcohols from Acetylenes and Aldehydes
Takai, Kazuhiko,Kataoka, Yasutaka,Utimoto, Kiitiro
, p. 1707 - 1708 (2007/10/02)
A variety of tantalum-alkyne complexes have been generated (but not isolated) by treatment of alkynes with low-valent tantalum derived from TaCl5 and zinc.These complexes add to carbonyl compounds in a one-to-one fashion to yield (E)-allylic alcohols, reg
