Platinum-catalyzed, one-pot tandem synthesis of indoles and isoquinolines via sequential rearrangement of amides and aminocyclization.
By using platinum(II) chloride as a Lewis acid catalyst, concise and efficient syntheses of indole carbamates, 1,2-dihydroisoquinoline carbamates, macrocyclic indole carbamates, indole ureas, and indole phosphoranes have been achieved via tandem Hofmann-type rearrangement of 2-alkynylbenzamides and 2-alkynylbenzylamides, nucleophilic addition of alcohols and amines to the isocyanate intermediates, and intramolecular aminocyclization of the thus-formed carbamates and ureas to 2-alkynyl functions. A variety of nucleophiles such as alcohols, amines, and stable Wittig reagents could be introduced to the highly electrophilic carbon of the isocyanate intermediates derived from amides. We observed enhancement of the reaction rates when the reactions were run under microwave irradiation.
Faculty of Pharmaceutical Sciences, Hiroshima International University, 5-1-1 Hirokoshingai, Kure, Hiroshima 737-0112, Japan.
Noriko
N
Okamoto
Kei
K
Takeda
Reiko
R
Yanada
D000577:Amides / Q000737:chemistry*; D002219:Carbamates / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D003500:Cyclization; D007202:Indicators and Reagents / Q000737:chemistry; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry; D007546:Isoquinolines / Q000138:chemical synthesis* / Q000737:chemistry; D058116:Lewis Acids / Q000737:chemistry*; D008872:Microwaves; D015394:Molecular Structure; D010984:Platinum / Q000737:chemistry*
D000577:Amides; D002219:Carbamates; D007202:Indicators and Reagents; D007211:Indoles; D007546:Isoquinolines; D058116:Lewis Acids; D010984:Platinum