2-Phenylbenzothiazoline as a Reducing Agent in the Conjugate Reduction of α,β-Unsaturated Carbonyl Compounds

Fragment Coupling and the Construction of Quaternary Carbons Using Tertiary Radicals Generated Fromtert-AlkylN-Phthalimidoyl Oxalates By Visible-Light Photocatalysis

“…Methyl vinyl ketone (MVK), acrylonitrile, benzyl methacrylate and methacrylonitrile were distilled from neat solutions prior to use. All reaction components Hantzsch ester 4 , 38 4,4- d 2 -Hantzsch ester 48 , 27a 4-Me Hantzsch ester 6 , 39 4-Ph Hantzsch ester 7 , 39 2-Ph-benzothiazoline 8 , 40 N , N ’-dimethyl-2-phenylbenzimidazoline 9 , 19b N -methylacridane 10 , 41 , i -Pr 2 NEt•HBF 4 , 14 methyl 2-(bromomethyl)acrylate ( 35 ), 42 methyl 2-(chloromethyl)acrylate ( 37 ), 43 ( E )-methyl 3-bromoacrylate ( 38 ), 44 α-(chloromethyl)styrene ( 40 ), 45 α-(bromomethyl)styrene ( 32 ) 45 were prepared according to literature procedures. Usually one representative coupling reaction and yield of the product is described in detail; isolated yields reported in the Results section are the average yields obtained from duplicate experiments.…”

A Hantzsch Amido Dihydropyridine as a Transfer Hydrogenation Reagent for α,β-Unsaturated Ketones

“…While this is often very effectively accomplished through the use of metal catalysts under an atmosphere of hydrogen gas, it is frequently desirable to avoid expensive and toxic metal catalysts and the explosive nature of H 2 . For these reasons, over the last several decades a significant quantity of research effort has been expended on the development of transfer hydrogenation methods that avoid such disadvantages. − Further avoiding metallocatalysts, the organic hydride donors have captured recent attention including benzothiazolines and related species − and the Hantzsch dihydropyridines . Of course, biological systems effect transfer hydrogenation transformations via enzymes that utilize the organic hydride-donating cofactors FADH and NAD­(P)­H .…”

2-Phenyl-2,3-dihydrobenzo[d]thiazole: A Mild, Efficient, and Highly Active in situ Generated Chemoselective Reducing Agent for the One-Pot Synthesis of 5-Monoalkylbarbiturates in Water

“…25 The reducing ability of benzothiazoline was demonstrated by the pioneering work of Chikashita and co-workers in early 1980s, where they used it for the reduction of α,β-unsaturated carbonyl compounds assisted by the substoichiometric amount of Lewis acid. 26 However, this work has not re-ceived much attention and the reducing ability of benzothiazoline has not been extensively studied until Zhu and Akiyama in 2009 used it as a hydrogen source in the asymmetric transfer hydrogenation of ketimines. 27 To the best of our knowledge, this is the first ever report to demonstrate the use of in situ generated benzothiazoline as a mild and efficient chemoselective reducing agent for the one-pot synthesis of 5-monoalkylbarbiturates under mild reaction conditions.…”