Iridium-Catalyzed Hydrocarboxylation of 1,1-Dimethylallene: Byproduct-Free Reverse Prenylation of Carboxylic Acids
摘要:
Exposure of carboxylic acids 1a-12a to commercially available 1,1-dimethylallene in the presence of substoichiometric quantities of an iridium catalyst prepared in situ from [ir(cod)Cl](2) and BIPHEP provides the corresponding 1,1-dimethylallyl (reverse prenyl) esters 1b-12b in 74-92% isolated yield. This protocol represents the first branch-regioselective allene hydrocarboxylation. Stoichiometric byproducts are not generated in this process and protecting groups are not required for alcohols, phenols, and indolic amines.
Diastereoselective Ireland–Claisen rearrangements of substituted allyl β-amino esters: applications in the asymmetric synthesis of C(5)-substituted transpentacins
作者:Stephen G. Davies、Ai M. Fletcher、James A. Lee、Paul M. Roberts、Myriam Y. Souleymanou、James E. Thomson、Charlotte M. Zammit
DOI:10.1039/c4ob00274a
日期:——
The diastereoselective Ireland–Claisen rearrangement of a range of substituted allyl β-amino esters gave the corresponding enantiopure α-substituted-β-amino esters with good diastereoselectivity. The application of this methodology in the asymmetric synthesis of a range of C(5)-substituted 1,2-anti-1,5-syn-transpentacins was demonstrated by the rearrangement of a range of β-amino esters derived from
Iridium-Catalyzed Hydrocarboxylation of 1,1-Dimethylallene: Byproduct-Free Reverse Prenylation of Carboxylic Acids
作者:In Su Kim、Michael J. Krische
DOI:10.1021/ol702914p
日期:2008.2.1
Exposure of carboxylic acids 1a-12a to commercially available 1,1-dimethylallene in the presence of substoichiometric quantities of an iridium catalyst prepared in situ from [ir(cod)Cl](2) and BIPHEP provides the corresponding 1,1-dimethylallyl (reverse prenyl) esters 1b-12b in 74-92% isolated yield. This protocol represents the first branch-regioselective allene hydrocarboxylation. Stoichiometric byproducts are not generated in this process and protecting groups are not required for alcohols, phenols, and indolic amines.