observed to give N-substituted aryl glycine derivatives in good to excellent yields (up to 93 %) from (ortho-hydroxymethyl)aryl benzoates. A cascade mechanism was proposed for the generation and in situ conjugateaddition of the ortho-quinone methides. This mechanism is strongly supported by our subsequent findings that tertiary amines could promote the process. Different functional groups on the (
[GRAPHICS]A highly stereoselective intramolecular cycloaddition of an indole tethered to an aza-ortho-xylylene intermediate effects the rapid construction of a substantial portion of the ring system of the cytotoxic natural product communesin B. An analogous cycloaddition involving an orthoquinone methide intermediate provides an adduct that clearly revealed that the structural assignment for nomofungin was in error.
Phenoxy-Dialkoxy Borates as a New Class of Readily Prepared Preactivated Reagents for Base-Free Cross-Coupling
作者:Marco Paladino、Michele Boghi、Dennis G. Hall
DOI:10.1002/ejoc.201900993
日期:2019.10.17
facile peparation, and base‐free cross‐coupling of a newclass of phenoxy‐dialkoxy adducts of organoboronic acids is described. These adducts form under ambient conditions, at a significantly lower temperature and with a weaker base compared to the conditions required for the preparation of trialkoxyborates. Moreover, they are soluble in most common organic solvents.