The Alder ene reaction can be conducted at low temperatures when one of these compounds is used to activate the enophile.
The CBS oxazaborolidine catalyst acts both as a chiral auxiliary and as one of these compounds. The Alder ene reaction can be conducted at low temperatures when one of these compounds is used to activate the enophile. These compounds complex to carbonyls, enabling them to be attacked by a silyl enol ether in the Mukaiyama variants of the Michael addition and the aldol condensation. One of these compounds is used to catalytically activate an acid halide so it can be nucleophilically attacked by a benzene ring in the (*) Friedel-Crafts acylation. Common examples of these compounds include boron trifluoride, titanium tetrachloride, and aluminum trichloride. For 10 points, name these compounds which, according to the theory of an American chemist, accept electron pairs.
The CBS oxazaborolidine catalyst acts both as a chiral auxiliary and as one of these compounds.
Lewis acids [prompt on "acids"]