title: Highly stereoselective synthesis of homoallylic amines based on addition of allyltrichlorosilanes to benzoylhydrazones.
abstract: Allyltrichlorosilanes reacted with benzoylhydrazones in DMF without the use of any catalyst to afford the corresponding homoallylic benzoylhydrazines in good to high yields. The reactions proceeded at 0 degrees C to room temperature under mild conditions. In addition, it was found that the reactions tolerated well the steric hindrance of hydrazones and allyltrichlorosilanes. Indeed, ketone-derived benzoylhydrazones reacted with allyltrichlorosilane smoothly to afford the corresponding N'-tert-alkyl-N-benzoylhydrazines in high yields. In crotylation with (E)- and (Z)-crotyltrichlorosilanes, syn- and anti-adducts were stereospecifically obtained, respectively. These reactions are most likely to proceed via a cyclic chairlike transition state where the R group takes an axial position. When alpha-heteroatom-substituted chiral benzoylhydrazones were used, high anti-diastereoselectivities were observed. These adducts can be readily converted to homoallylic amines in high yields without epimerization.
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, CREST, Japan Science and Technology Corporation, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Hirabayashi
authors.forename: C
authors.initials: C
authors.lastname: Ogawa
authors.forename: M
authors.initials: M
authors.lastname: Sugiura
authors.forename: S
authors.initials: S
authors.lastname: Kobayashi