1-Methoxy-2-alkanones are prepared from ate-complexes formed from 1,2-dimethoxyethenyllithium and trialkylboranes by the reaction with BF3:Et2O, followed by basic hydrogen peroxide oxidation.
Photoinduced Carboborative Ring Contraction Enables Regio- and Stereoselective Synthesis of Multiply Substituted Five-Membered Carbocycles and Heterocycles
作者:Shengfei Jin、Vu T. Nguyen、Hang T. Dang、Dat P. Nguyen、Hadi D. Arman、Oleg V. Larionov
DOI:10.1021/jacs.7b07128
日期:2017.8.23
herein a photoinduced carboborative ringcontraction of monounsaturated six-membered carbocycles and heterocycles. The reaction produces substituted five-membered ring systems stereoselectively and on preparative scales. The products feature multiple stereocenters, including contiguous quaternary carbons. We show that the reaction can serve as a synthetic platform for ring system alteration of natural products
作者:Herbert C. Brown、M.Mark Midland、Alan B. Levy、H.C. Brown、R.B. Wetherill、Akira Suzuki、Sunao Sono、Mitsuomi Itoh
DOI:10.1016/s0040-4020(01)83446-3
日期:1987.1
excellent yields of secondary amines. Furthermore, the stereochemistry of the original carbon-boron bond is retained. The mechanism of these reactions is discussed and the reaction applied to the synthesis of N-alkyl- and N-arylaziridines.
[reaction: see text] Exposure of monocarbonyl iodonium ylides, generated by the ester exchange of (Z)-(2-acetoxyvinyl)-lambda(3)-iodanes with EtOLi, to organoboranes results in a 1,2-shift of a carbon ligand from boron to the ylide carbons, which probably generates hitherto uncharacterized alpha-boryl ketones.
Trialkylboranes derived from terminal, cyclic and bicyclic olefins via hydroboration with 5 mole percent excess borane undergo ready redistribution with boron trichloride at 110° to give the corresponding alkyldichloroboranes, providing a convenient synthesis of such derivatives. On the other hand, trialkylboranes derived from internal olefins, such as 3-hexene, undergo this reaction more sluggishly