Radical Azidonation of Benzylic Positions with Iodonium Azide

An Azido-Hanessian Reaction

“…Recently, we reported that IN 3 4 reacts with benzyl ethers, such as 1, to form a-azido benzyl ethers, such as 2 (Scheme 1). 5 The idea was conceived that reaction of a benzal acetal 3 would give a similar reaction to form 4.…”

Chemical versatility of azide radical: journey from a transient species to synthetic accessibility in organic transformations

“…In 2001, Bols et al reported a radical substitution reaction with azide on a limited number of benzyl ethers using IN 3 as a reagent in refluxing CH 3 CN to offer a-azido ethers in high yields in the range of 74-98% (Scheme 70a). 200 Most importantly, the electron-donating capacity at the benzylic position was crucial for accomplishing this reaction. Later, the same idea was conceived for the azidonation of benzal acetals; however, a ring opening reaction involving the azide radical occurred to transform into b-azidobenzoate by this reagent (Scheme 70b).…”

Gold-Catalyzed Benzylic Azidation of Phthalans and Isochromans and Subsequent FeCl₃-Catalyzed Nucleophilic Substitutions

“…[9][10][11][12][13] We have continuously investigated the iron [14][15][16][17][18][19][20] -or gold [21][22][23] -catalyzed activation at the benzylic position of various skeletons accompanied by the benzylic C-O bond cleavage. During these investigations, the benzylic position of phthalan (1; n=1) as a benzene fused cyclic ether was found to be directly azidated in the presence of a gold catalyst and trimethylsilylazide (TMSN 3 ) without the C-O bond cleavage to give the 1-azido phthalan (2) (Chart 1).…”

“…During these investigations, the benzylic position of phthalan (1; n=1) as a benzene fused cyclic ether was found to be directly azidated in the presence of a gold catalyst and trimethylsilylazide (TMSN 3 ) without the C-O bond cleavage to give the 1-azido phthalan (2) (Chart 1). The direct azidations at the benzylic position of phthalan and isochroman (1; n=2) were previously accomplished using stoichiometric iodine reagents [9][10][11] in the presence of azido sources, such as TMSN 3 and NaN 3 . Although gold catalysts were used for the C-C and C-N bond formation on the benzylic position via C-H bond activation, 12,13) the azidation method was never reported in the literature.…”