The chemistry of acylated quinone imine ketals. Nucleophilic and organolithium addition reactions

Trimethylsilyl Trifluoromethanesulfonate

“…120 However, aromatization has occurred for 4-(N-benzoylamino)-4-phenyl-2,5-cyclohexadienone dimethyl ketal (eq 82). 121 This method has also allowed the development of 1-methylcyclopropyl ether as a protecting group for the hydroxyl moiety which is prepared regioselectively from terminal acetonides. The allylation of acetals is also promoted by TMSOTf.…”

“…α,β-Unsaturated carbonyl compounds are obtained when these substituted propargyl silyl ethers are treated with TMSOTf followed by the addition of water (eq 120). 183 (121) Iron carbene complexes bearing chirality at the carbene ligand can be generated from optically pure bimetallic (chromium-iron) complexes by the addition of 1 equiv of TMSOTf in the presence of an olefin, which in situ undergoes an asymmetric cyclopropanation. Excellent ee's are obtained when the reaction is carried out with gem-disubstituted olefins (eq 122).…”

An Efficient Coupling of p‐Quinone Mono‐Imine Ketals and Aryl/Alkyl Thiols: Rapid Synthesis of Biaryl/Aryl–Alkyl Sulfides

“…There is a need for the development of advantageous methods to synthesize biaryl sulfides regioselectively. The reaction of compound 1 proceeds through activation of the imine moiety with Brønsted acid to furnish the regioisomer selectively by nucleophilic attack on QIK . Initially, we envisaged that the acid catalyst may promote reaction through attack of thiophenol at the C‐3 position of QIK to afford product B through Michael addition reaction followed by aromatization.…”

ChemInform Abstract: Practical Synthesis of p‐ and o‐Amino‐ and Methoxyphenolic Anthraquinones.

“…Thep roblematic nature of the existing methods for the construction of p-substituted aminophenolic anthraquinones is documented by the isolated examples [4,16] and limited success with complex substrates (see Figure 1b). [17,18] In the latter cases directed toward the total synthesis of dynemycin, Myers [17] and Danishefsky [18] reported formation of undesired products C [17] and D [17,18] instead of the desired amino anthraquinone advanced intermediates (E and thence F, Figure 1b)t hrough aH auser-Kraus type [19][20][21] reaction from the corresponding cyanophthalide (A)a nd iminoquinones (B) ( Figure 1b).…”