Direct Lactonization of Alkenols via Osmium Tetroxide-Mediated Oxidative Cleavage
摘要:
A highly efficient, mild, and simple protocol is presented for the tandem OsO4-mediated oxidative cleavage/oxidative lactonization of alkenols to lactones. The protocol couples the OsO4-catalyzed oxidative cleavage of olefins with Oxone as the co-oxidant with the direct oxidation of aldehydes in alcoholic solvents to their corresponding esters.
Unprecedented 3-amino-4-amido-1H-isochromenes have been prepared in three steps from protected ortho-(hydroxymethyl)benzaldehyde, with the introduction of three diversity inputs, through a Ugi reaction followed by intramolecular nucleophilic substitution.
作者:Chun-Hua Yang、Meng Han、Wenyan Li、Ningning Zhu、Zhenzhen Sun、Junjie Wang、Zhantao Yang、Yue-Ming Li
DOI:10.1021/acs.orglett.0c01685
日期:2020.7.2
Direct intramolecular aminoboration of sulfonamidoallenes was realized using BCl3 as a boron source. The reactions benefited from the interaction between BCl3 and sulfonamides and provided a variety of borylvinyl heterocycles in good isolated yields. When chiral substrates were involved in the reactions, high stereoselectivity was observed, as can be ascertained by single-crystal X-ray diffraction
Synthetic studies on the solanacol ABC ring system by cation-initiated cascade cyclization: implications for strigolactone biosynthesis
作者:Kinga Chojnacka、Stefano Santoro、Radi Awartani、Nigel G. J. Richards、Fahmi Himo、Aaron Aponick
DOI:10.1039/c1ob05751k
日期:——
We report a new method for constructing the ABC ring system of strigolactones, in a single step from a simple linear precursor by acid-catalyzed double cyclization. The reaction proceeds with a high degree of stereochemicalcontrol, which can be qualitatively rationalized using DFT calculations. Our concise synthetic approach offers a new model for thinking about the (as yet) unknown chemistry that
Enantioselective desymmetrization of prochiral 1,3-dinitropropanes via organocatalytic allylic alkylation
作者:Soumya Jyoti Singha Roy、Santanu Mukherjee
DOI:10.1039/c3cc47645f
日期:——
An enantioselective desymmetrization of prochiral 1,3-dinitropropanes has been developed which proceeds via enantiogroup differentiating organocatalyticallylicalkylation. Densely functionalized products with two vicinal stereocenters were obtained generally with good to excellent diastereoselectivity (up to >20 : 1 dr) and superb enantioselectivity (up to >99 : 1 er).