Ionic Hydrogenation

An intermolecular Diels–Alder approach to (±)-isoacanthodoral

“…It was necessary to prepare more Diels-Alder adducts, to separate isomer 7 required for the synthesis, and then to repeat the reaction sequence leading to alcohol 28. It has been reported that ionic hydrogenation can be performed using trialkylsilanes and a strong acid or boron trifluoride (26)(27)(28)(29)(30). Under these conditions, an a,P-unsaturated ketone can be reduced to the saturated ketone or alcohol, depending on the quantities of the acid and the reducing agent used.…”

Ionic and Organometallic‐Catalyzed Organosilane Reductions

“…1). 3,70,71 On the other hand, simple mixtures of organosilicon hydrides and compounds with weakly electrophilic carbon centers such as ketones and aldehydes are normally unreactive unless the electrophilicity of the carbon center is enhanced by complexation of the carbonyl oxygen with Brønsted acids 3,70 -73 or certain Lewis acids (Eq. 2).…”

“…2). 1,70,71,74,75 Using these acids, hydride transfer from the silicon center to carbon may then occur to give either alcohol-related or hydrocarbon products.…”

“…63). 70 Vinylcyclopropane is reduced to ethylcyclopropane within 30 minutes under similar conditions (Eq. 64).…”

“…The Et 3 SiH/TFA combination can also lead to the trifluoroacetate and toluene derivatives when used with some aryl aldehydes. 69 The reduction of aldehydes with the combination Et 3 SiH/BF 3 •OEt 2 gives both the alcohol and the symmetrical ether, 70 as do the Et 3 SiH/TFA (and other acids) combinations. 313 Addition of boron trifluoride etherate to a mixture of 1-octanal and triethylsilane leads to the formation of di-n-octyl ether in 66% yield and n-octyl alcohol in 34% yield (Eq.…”