Asymmetric C–H insertion of Rh(II) stabilized carbenoids into acetals: A C–H activation protocol as a Claisen condensation equivalent
摘要:
The dirhodium tetraprolinate, Rh-2(S-DOSP)(4) is an efficient catalyst in an enantio selective C-H activation protocol. Rh-2(S-DOSP)(4) catalyzed decomposition of aryldiazoacetates or vinyldiazoacetates results in the formation of transient rhodium carbenoid intermediates. These inter-mediates are capable of selectively inserting into the C-H bond of acetals. The resulting products are protected P-keto esters, and so the C-H activation protocol can be considered as strategically equivalent to the Claisen condensation. (c) 2005 Elsevier B.V. All rights reserved.
Enantioselective synthesis of anti- and syn-β-hydroxy-α-phenyl carboxylates via boron-mediated asymmetric aldol reaction
作者:P. Veeraraghavan Ramachandran、Prem B. Chanda
DOI:10.1039/c3cc40860d
日期:——
enantioselective synthesis of anti- and syn-beta-hydroxy-alpha-phenyl carboxylates has been achieved by the proper choice of solvent, temperature, alkoxy group, and amine for the diisopinocampheylboron-mediated asymmetric enolization-aldolization of phenylacetates. The pure diastereomers can be readily separated by column chromatography.
Asymmetric C–H insertion of Rh(II) stabilized carbenoids into acetals: A C–H activation protocol as a Claisen condensation equivalent
作者:Huw M.L. Davies、Jaemoon Yang、Joachim Nikolai
DOI:10.1016/j.jorganchem.2005.08.026
日期:2005.12
The dirhodium tetraprolinate, Rh-2(S-DOSP)(4) is an efficient catalyst in an enantio selective C-H activation protocol. Rh-2(S-DOSP)(4) catalyzed decomposition of aryldiazoacetates or vinyldiazoacetates results in the formation of transient rhodium carbenoid intermediates. These inter-mediates are capable of selectively inserting into the C-H bond of acetals. The resulting products are protected P-keto esters, and so the C-H activation protocol can be considered as strategically equivalent to the Claisen condensation. (c) 2005 Elsevier B.V. All rights reserved.