Rhodium-Catalyzed Asymmetric Addition of Arylboronic Acids to Indolylnitroalkenes
作者:Junwei Xing、Guihua Chen、Peng Cao、Jian Liao
DOI:10.1002/ejoc.201101648
日期:2012.2
bioactive structures. Most approaches to access chiral indolylnitroethanes involve organocatalyzed or metal-catalyzed asymmetric FriedelCrafts reaction of indoles with nitroalkenes. We have developed an efficient approach to optically pure a-aryl-3-indolylnitroethanes through rhodium-catalyzed asymmetric 1,4-addition of arylboronicacids to indolylnitroalkenes. Excellent yields (up to 99?%) and enantiomeric
The Diazo Route to Diazonamide A. Studies on the Indole Bis-oxazole Fragment
作者:James R. Davies、Peter D. Kane、Christopher J. Moody
DOI:10.1021/jo0509760
日期:2005.9.1
Various approaches to the indole bis-oxazole fragment of the marine secondary metabolite diazonamide A are described, all of which feature dirhodium(II)-catalyzed reactions of diazocarbonyl compounds in key steps. Thus, 3-bromophenylacetaldehyde is converted into an α-diazo-β-ketoester, dirhodium(II)-catalyzed reaction of which with N-Boc-valinamide resulted in N-H insertion of the intermediate rhodium
Studies towards the synthesis of diazonamide A. Synthesis of the 4-(oxazol-5-ylmethyl) aryltryptamine fragment
作者:Mark C Bagley、Christopher J Moody、Adrian G Pepper
DOI:10.1016/s0040-4039(00)01121-7
日期:2000.8
The oxazole substituted 4-aryltryptamine 5, a potential intermediate for the synthesis of the marine natural product diazonamide A 1, has been synthesised.
作者:Michael E. Muratore、Chloe A. Holloway、Adam W. Pilling、R. Ian Storer、Graham Trevitt、Darren J. Dixon
DOI:10.1021/ja9024885
日期:2009.8.12
An enantioselective Bronsted acid-catalyzed N-acyliminium cyclization cascade of tryptamines with enol lactones to form architecturally complex heterocycles in high enantiomeric excess has been developed. The reaction is technically simple to perform as well as atom-efficient and may be coupled to a gold(1)-catalyzed cycloisomerization of alkynoic acids whereby the key enol lactone reaction partner is generated in situ. Employing up to 10 mol% bulky chiral phosphoric acid catalysts in boiling toluene allowed the product materials to be generated in good overall yields (63-99%) and high enantioselectivities (72-99% ee). With doubly substituted enol lactones, high diastereo- and enantioselectivities were obtained, thus providing a new example of a dynamic kinetic asymmetric cyclization reaction.
Model Studies towards Diazonamide A: Synthesis of the Heterocyclic Core
作者:K. C. Nicolaou、Scott A. Snyder、Klaus B. Simonsen、Alexandros E. Koumbis