A simple and efficient procedure was developed for the preparation of a variety of aryl, hetero aryl and alkyl N-sulfinylimines (2b-2u) with excellent yields (85–94%) using tungstophosphoric acid as catalyst. Also, this new synthetic protocol features high conversion, shorter reaction time, a straight forward and simple work up procedure. Catalyst was recycled for 10 times without much loss in activity
KHSO<sub>4</sub>-Mediated Condensation Reactions of <i>tert</i>-Butanesulfinamide with Aldehydes. Preparation of <i>tert</i>-Butanesulfinyl Aldimines
作者:Yong Qin、Zhiyan Huang、Min Zhang、Yin Wang
DOI:10.1055/s-2005-865234
日期:——
tert-butanesulfinyl aldimines 1 were prepared by direct condensation of chiral tert-butanesulfinamide 3 with aldehydes 2 in high yields in the presence of KHSO 4 . The main advantage of KHSO 4 is that it is applicable to the condensation reactions of a variety of aldehydes, including electron deficient and electron rich (hetereo)aromatic aldehydes, as well as aliphatic aldehydes.
Dramatic Effect of γ-Heteroatom Dienolate Substituents on Counterion Assisted Asymmetric Anionic Amino-Cope Reaction Cascades
作者:Pradipta Das、Michael D. Delost、Munaum H. Qureshi、Jianhua Bao、Jason S. Fell、Kendall N. Houk、Jon T. Njardarson
DOI:10.1021/jacs.1c00745
日期:2021.4.21
appear to proceed via the same pathway as the fluoride albeit with the added twist of a 3-exo-trig cyclization to yield chiral cyclopropane products with three stereocenters. When this same class of nucleophiles is substituted with a γ-nitro group, the Mannich-initiated cascade is now diverted to a β-lactam product instead of the amino-Cope pathway. These anionic asymmetric cascades are solvent- and counterion-dependent
Asymmetric aziridination by reaction of chiral N-sulfinylimines with sulfur ylides: Stereoselectivity improvement by use of tert-butylsulfinyl group as chiral auxiliary
作者:JoséL García Ruano、Inmaculada Fernández、Miriam del Prado Catalina、Ana Alcudia Cruz
DOI:10.1016/s0957-4166(96)00448-x
日期:1996.12
Chiraltert-butylsulfinylgroup has been shown to be the chiralauxiliary of choice for the asymmetric aziridination of N-sulfinyliminas. Moreover, the sense of the asymmetric induction can be tuned in two ways: the chirality at the tert-butylsulfinyl Sulfur, or the nature of the methylene transfer reagent used. Thus, both aziridines 10(Ss,S) and 10(Rs,R), epimeric at C-2, were obtained in enantiomerically
New Class of Anion-Accelerated Amino-Cope Rearrangements as Gateway to Diverse Chiral Structures
作者:Isaac Chogii、Pradipta Das、Jason S. Fell、Kevin A. Scott、Mark N. Crawford、K. N. Houk、Jon T. Njardarson
DOI:10.1021/jacs.7b07319
日期:2017.9.20
We report useful new lithium-assisted asymmetric anion-accelerated amino-Cope rearrangement cascades. A strategic nitrogen atom chiral auxiliary serves three critical roles, by (1) enabling in situ assembly of the chiral 3-amino-1,5-diene precursor, (2) facilitating the rearrangement via a lithiumenolate chelate, and (3) imparting its influence on consecutive inter- or intramolecular C-C or C-X bond-forming