of catalytic amounts of optically active aminoalcohols, the irradiation of α-disubstituted indanones, tetralones and propiophenones bearing at least one hydrogen in the γ-position led to Norrish type II cleavage compounds which were obtained with enantiomeric excesses reaching 89%. The influence of the reaction conditions (temperature, wavelength of the UV light and nature of the alcohol) has been analyzed
Surfactant Micelles Enable Metal-Free Spirocyclization of Keto-Ynamides and Access to Aza-Spiro Scaffolds in Aqueous Media
作者:Frédéric Beltran、Andrea V. Vela-Gonzalez、Tatiana Knaub、Marc Schmutz、Marie Pierre Krafft、Laurence Miesch
DOI:10.1002/ejoc.201901441
日期:2019.11.10
Naturally occurring aza‐spiro scaffolds are synthesized in aqueousmicellar solutions of a cationic surfactant without metal catalysis. Dynamic light scattering and cryogenic transmission electron microscopy monitoring revealed the incorporation of the substrate and the presence of the reaction products in the micelles.
Intramolecular Alkynylogous Mukaiyama Aldol Reaction Starting from Bicyclic Alkanones Tethered to Alkynyl Esters: Formal Total Synthesis of (±)-Hamigeran B
esters tethered to bicycloalkanones leads to the formation of tricyclic allenoates with total diasteroselectivity at the ring junction. An intramolecular alkynylogous Mukaiyama aldol reaction promoted by a TBSOTf/NEt3 dual activation is involved. This novel methodology was illustrated by a formaltotalsynthesis of (±)‐hamigeran B.
选择环:叔丁基二甲基甲硅烷基叔丁基硫酸盐(TBSOTf)/ NEt 3处理与双环烷酮相连的炔基酯会形成三环烯酸酯,在环结处具有总的非对映选择性。涉及由TBSOTf / NEt 3双重激活促进的分子内的醇酸Mukaiyama aldol反应。(±)-hamigeran B的正式总合成说明了这种新颖的方法。
Deprotection of ketone dimethylhydrazones using lipases
Deprotection of ketone dimethylhydrazone compounds with porcine pancreatic lipase (PPL) as a biocatalyst is described.
描述了用猪胰脂肪酶(PPL)作为生物催化剂对酮二甲基hydr化合物的脱保护。
Catalytic Aerobic Oxidative Cleavage of Oximes, Tosylhydrazones and N,N-Dimethylhydrazones to Carbonyl Compounds
作者:Gonzalo Blay、Elisabeth Benach、Isabel Fernández、Sales Galletero、José R. Pedro、Rafael Ruiz
DOI:10.1055/s-2000-6347
日期:——
A new method for the aerobic oxidative cleavage of the C=N double bond of oximes and, tosyl- and N,N-dimethylhydrazones of ketones to yield their corresponding carbonyl compounds, with a Ni(II) complex catalyst, oxygen and pivalaldehyde has been developed.