α-Nitro Ketones; 8¹. Nitration of Enol Acetates with Trifluoroacetic Anhydride and Ammonium Nitrate

Stereoselective Alkylations of Chiral Nitro Imine and Nitro Hydrazone Dianions. Synthesis of Enantiomerically Enriched 3-Substituted 1-Nitrocyclohexenes

“…8 Accordingly, cyclohexanone was converted into the corresponding enol acetate, which was then transformed into 2-nitrocyclohexanone according to the method of Zajac. 31 Treatment of this nitro ketone with the acetate salt of the appropriate chiral amine (benzene, reflux) afforded the desired nitro imines. The initial set of alkylation substrates is indicated in Table 1.…”

Synthesis, reactions, and applications of fluorine-containing multifunctional carbon compounds

“…Treatment of several a-fluoro ketones or esters 1 having one or two additional fluorine or bromine atoms at the a-position of the carbonyl group, with zinc and trimethylsilyl chloride in acetonitrile gave the corresponding enol silylethers 2 (M = TMS) (Scheme 1) [11]. Although electrophilic nitration of the enol silylethers and the corresponding lithium or sodium enolates 2 (M = Li, Na) [12][13][14] was attempted, under various conditions (PrONO 2 /TBAF [15], O 2 NBF 4 /HF/Pyridine [16], or NH 4 ONO 2 /TFAA [17]), the desired compound 3 could not be obtained. Both electrophilic amination (R 2 NOR 0 ) [18] and sulfenylation (PhSCl, PhSSPh) of them were also unsuccessful.…”

“…The tetrafunctional carbon compounds thus far obtained, 9,10,[17][18][19]22, and 23, are not only new but also interesting from the viewpoint of physical properties.…”

Trifluoroacetic Anhydride

“…The use of TFAA delivers an amide of enhanced acidity and which is easily hydrolyzed in situ, thereby allowing a one-pot alkylation process (eq 15). 21 (15) Reaction of TFAA with ammonium nitrate provides an in situ source of trifluoroacetyl nitrate, which has been used for the nitration of enol acetates 22 and as an N-nitrating agent. 23 TFAA efficiently cleaves N-tosyl protecting groups from histidine (eq 16).…”