Asai S, Yabe Y, Goto R, Nagata S, Monguchi Y, Kita Y, Sajiki H, Sawama Y. Gold-Catalyzed Benzylic Azidation of Phthalans and Isochromans and Subsequent FeCl3-Catalyzed Nucleophilic Substitutions.
Chem Pharm Bull (Tokyo) 2015;
63:757-61. [PMID:
26423031 DOI:
10.1248/cpb.c15-00347]
[Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The benzylic positions of the phthalan and isochroman derivatives (1) as benzene-fused cyclic ethers effectively underwent gold-catalyzed direct azidation using trimethylsilylazide (TMSN3) to give the corresponding 1-azidated products (2) possessing the N,O-acetal partial structure. The azido group of the N,O-acetal behaved as a leaving group in the presence of catalytic iron(III) chloride, and 1-aryl or allyl phthalan and isochroman derivatives were obtained by nucleophilic arylation or allylation, respectively. Meanwhile, a double nucleophilic substitution toward the 1-azidated products (2) occurred at the 1-position using indole derivatives as a nucleophile accompanied by elimination of the azido group and subsequent ring opening of the cyclic ether nucleus produced the bisindolylarylmethane derivatives.
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