Synthesis of partially hydrogenated oxa[5] and oxa[6]helicenes from β-chlorovinylaldehydes
摘要:
Synthesis of partially hydrogenated oxa[5]helicenes is described starting from easily available beta-chlorovinylaldehydes. The short sequence involved a Suzuki-Miyaura type coupling between beta-chlorovinylaldehydes and arylboronic acids bearing ortho-methoxy groups. The presence of both the formyl and the methoxy groups allowed after reduction and demethylation respectively, the construction of the central dehydropyran ring. The molecular structure of the extended benzopyrene-based oxa[5]helicenes has been fully determined in solution and in the solid state. The strategy could be extended to oxa[6]helicene. Atroposelective Suzuki-Miyaura couplings were the key steps of the nonracemic preparation of oxa[5]helicenes. Ee observed are in good agreement with the theoretically calculated racemization barriers. (C) 2013 Elsevier Ltd. All rights reserved.
Synthesis of partially hydrogenated oxa[5] and oxa[6]helicenes from β-chlorovinylaldehydes
作者:Alexandre Requet、Amel Souibgui、Grégory Pieters、Sabrina Ferhi、Alicia Letaieff、Abel Carlin-Sinclair、Sylvain Marque、Jérome Marrot、Béchir Ben Hassine、Anne Gaucher、Damien Prim
DOI:10.1016/j.tetlet.2013.06.101
日期:2013.8
Synthesis of partially hydrogenated oxa[5]helicenes is described starting from easily available beta-chlorovinylaldehydes. The short sequence involved a Suzuki-Miyaura type coupling between beta-chlorovinylaldehydes and arylboronic acids bearing ortho-methoxy groups. The presence of both the formyl and the methoxy groups allowed after reduction and demethylation respectively, the construction of the central dehydropyran ring. The molecular structure of the extended benzopyrene-based oxa[5]helicenes has been fully determined in solution and in the solid state. The strategy could be extended to oxa[6]helicene. Atroposelective Suzuki-Miyaura couplings were the key steps of the nonracemic preparation of oxa[5]helicenes. Ee observed are in good agreement with the theoretically calculated racemization barriers. (C) 2013 Elsevier Ltd. All rights reserved.