Redox-Neutral Synthesis of β-Amino Aldehydes from Imines by an Alkynylation/Hydration Sequence
摘要:
N-Protected beta-amino aldehydes have been prepared starting from imines through a sequence involving a Zn-mediated direct alkynylation followed by a Ru-catalyzed anti-Markovnikov alkyne hydration. The rate and the efficiency of the latter reaction are enhanced by the use of microwave irradiation. The possibility to carry out a one-pot Ru-catalyzed hydration/oxidation process from a terminal alkyne to a carboxylic acid was demonstrated, which provided direct access to a N-protected beta-amino acid from the corresponding terminal alkyne.
The first highly efficient double Friedel–Crafts reaction of N-tosyl imines with anisole, phenol, thioanisole and analogues has been developed to produce the corresponding symmetric diarylmethanes and triarylmethanes with high regioselectivity in the presence of a catalytic amount of Bi2(SO4)3–TMSCl at room temperature.
Lewis base-catalyzed perfluoroalkylation of carbonyl compounds and aldimines with (perfluoroalkyl)trimethylsilanes (TMSCF3, TMSC2F5, and TMSC3F7) is described. The nitrogen- or oxygen-containing an...
first catalytic addition reactions of sulfonylimidates have been accomplished. In the presence of a catalytic amount of DBU (normally 5−10 mol %), sulfonylimidates reacted with several N-protected imines, methyl acrylate, and azodicarboxylate to afford the corresponding addition adducts, sulfonylimidates, in excellent yields. In the addition reactions to imines, high anti-selectivity was observed. A
磺酰亚胺酯的第一次催化加成反应已经完成。在催化量的 DBU(通常为 5-10 mol%)存在下,磺酰亚胺酯与几种 N 保护的亚胺、丙烯酸甲酯和偶氮二羧酸酯反应,以极好的收率提供相应的加合物磺酰亚胺酯。在与亚胺的加成反应中,观察到高抗选择性。还描述了从醛和磺酰亚胺酸酯直接形成 β-氨基酸衍生物的新方法。
Hf(IV)-Catalyzed Enantioselective Epoxidation of <i>N</i>-Alkenyl Sulfonamides and <i>N</i>-Tosyl Imines
作者:José Luis Olivares-Romero、Zhi Li、Hisashi Yamamoto
DOI:10.1021/ja211880s
日期:2012.3.28
Asymmetric epoxidation of allylic and homoallylic amine derivatives catalyzed by Hf(IV)-bishydroxamic acid complexes is described. Under similar conditions, aldimine and ketimine produced oxaziridines. The sulfonyl group is demonstrated to be an effective directing group for these transformations.
three-component couplingreaction of tetrafluoroethylene (TFE) and N-sulfonyl-substituted imines with silanes that furnishes a variety of fluorine-containing amines is disclosed. Stoichiometric experiments revealed that the aza-nickelacycles generated upon oxidative cyclization of TFE and N-sulfonyl-substituted imines on Ni(0) were identified as the key intermediates in this catalytic reaction. A single-crystal