Palladium(II)/Brønsted Acid-Catalyzed Enantioselective Oxidative Carbocyclization-Borylation of Enallenes

• Published in: Angewandte Chemie International Edition Vol. 54; no. 20; pp. 6024 - 6027
• Main Authors: Jiang, Tuo, Bartholomeyzik, Teresa, Mazuela, Javier, Willersinn, Jochen, Bäckvall, Jan-E.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 11.05.2015; WILEY‐VCH Verlag; Wiley; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: carbocyclization; Chemistry; Chemistry, Multidisciplinary; chiral anion; chiral phosphoric acid; Communications; Organic Chemistry; organisk kemi; oxidation; palladium; Physical Sciences; Science & Technology; BRONSTED ACID; TRANSITION-METAL CATALYSIS; carbocyclization; chiral phosphoric acid; oxidation; SPIRO PHOSPHORIC-ACIDS; PALLADIUM CATALYSIS; C-H ACTIVATION; ARYLATING CARBOCYCLIZATION; CARBON BOND FORMATION; SUBSTITUTED CONJUGATED DIENES; CHIRAL COUNTERION STRATEGY; chiral anion; palladium; ALPHA-ALLYLATION
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.201501048

An enantioselective oxidative carbocyclization–borylation of enallenes that is catalyzed by palladium(II) and a Brønsted acid was developed. Biphenol‐type chiral phosphoric acids were superior co‐catalysts for inducing the enantioselective cyclization. A number of chiral borylated carbocycles were synthesized in high enantiomeric excess. Biphenol‐type chiral phosphoric acids serve as co‐catalysts to induce enantioselectivity in the palladium(II)‐catalyzed oxidative carbocyclization–borylation of enallenes. The method was used to prepare a number of enantioenriched borylated carbocycles in high yields and enantioselectivities (up to 93 %). BQ=benzoquinone, pin=pinacolato.