145416-06-4Relevant articles and documents
Total Synthesis of (-)-Daphnezomines A and B
Li, Chao,Li, Luyang,Lu, Yunan,Wu, Jinbao,Xu, Guangpeng
supporting information, p. 15240 - 15245 (2020/10/20)
Daphnezomines A and B are structurally unusual Daphniphyllum alkaloids that contain a unique aza-adamantane core skeleton. Herein, a modular approach to these alkaloids is presented that exploits a diverse array of reaction strategies. Commencing from a chiral pool terpene-(S)-carvone, the azabicyclo[3.3.1]nonane backbone, which occurs widely in Daphniphyllum alkaloids, was easily accessed through a Sharpless allylic amination and a palladium-catalyzed oxidative cyclization. A protecting group enabled a stereoselective B-alkyl Suzuki-Miyaura coupling sequence and an Fe-mediated hydrogen atom transfer (HAT)-based radical cyclization were then applied to construct C6 and C8 stereocenters. A final epimer locking strategy enabled the assembly of the highly congested aza-adamantane core, thereby achieving the first total synthesis of (-)-daphnezomines A and B in 14 steps.
Overcoming equilibrium issues with carbonyl reductase enzymes
Calvin, Susan J.,Mangan, David,Miskelly, Iain,Moody, Thomas S.,Stevenson, Paul J.
experimental part, p. 82 - 86 (2012/05/31)
We report herein the screening, optimisation and scale up to 100 g of a bioreduction process that employs an in situ product removal (ISPR) technique to overcome the inherent equilibrium problem associated with the coupled-substrate approach to biocatalyt
Stereospecificity of the Au(I)-catalyzed reaction of 1-alkynyl-bicyclo[4.1. 0]-heptan-2-ones with nucleophiles
Labsch, Stephan,Ye, Shute,Adler, Andreas,Neudoerfl, Joerg-Martin,Schmalz, Hans-Guenther
scheme or table, p. 1745 - 1751 (2010/10/03)
The stereospecificity of the Au(I)-catalyzed reaction of 1-alkynyl-bicyclo[4.1.0]-heptan-2-ones with nucleophiles was investigated. The substrates were prepared in non-racemic form (up to 88% ee) through parallel kinetic resolution (CBS reduction) and reo
Mild and expedient asymmetric reductions of α,β-unsaturated alkenyl and alkynyl ketones by TarB-NO2 and mechanistic investigations of ketone reduction
Eagon, Scott,Delieto, Cassandra,McDonald, William J.,Haddenham, Dustin,Saavedra, Jaime,Kim, Jinsoo,Singaram, Bakthan
experimental part, p. 7717 - 7725 (2011/01/05)
A facile and mild reduction procedure is reported for the preparation of chiral allylic and propargyl alcohols in high enantiomeric purity. Under optimized conditions, alkynyl and alkenyl ketones were reduced by TarB-NO 2 and NaBH4 at 25 °C in 1 h to produce chiral propargyl and allylic alcohols with enantiomeric excesses and yields up to 99%. In the case of α,β-unsaturated alkenyl ketones, α-substituted cycloalkenones were reduced with up to 99% ee, while more substituted and acyclic derivatives exhibited lower induction. For α,β-ynones, it was found that highly branched aliphatic ynones were reduced with optimal induction up to 90% ee, while reduction of aromatic and linear aliphatic derivatives resulted in more modest enantioselectivity. Using the (l)-TarB-NO2 reagent derived from (l)-tartaric acid, we routinely obtained highly enantioenriched chiral allylic and propargyl alcohols with (R) configuration. Since previous models and a reduction of a saturated analogue predicted propargyl products of (S) configuration, a series of new mechanistic studies were conducted to determine the likely orientation of aromatic, alkenyl, and alkynyl ketones in the transition state.
Highly enantioselective and regioselective carbonyl reduction of cyclic α,β-unsaturated ketones using TarB-N02 and sodium borohydride
Kim, Jinsoo,Bruning, John,Park, Kevin E.,Lee, David J.,Singaram, Bakthan
supporting information; experimental part, p. 4358 - 4361 (2009/12/24)
Asymmetric 1,2-reduction of α,β-unsaturated ketones using TarB-NO2 and NaBH4 Is reported. Simple cycloalkenones give products In low enantiomeric excess. However, cycloalkenones with a-substituents, such as halides, alkyl, and aryl, have been enantioselectively reduced with this system to yield chiral allylic alcohols In enantiomeric excess up to 99%. The starting materials for TarB-N02 are inexpensive, and the boronlc acid can be easily recovered In high yield by a simple acid extraction.
Copper-catalyzed preparation of ketones bearing a stereogenic center in α position
Soorukram, Darunee,Knochel, Paul
, p. 3686 - 3689 (2008/02/12)
A highly enantioselective synthesis of α-alkylated and -arylated ketones can be achieved by using a reaction sequence consisting of a stereoselective anti-SN2′ allylic substitution in the presence of CuCN·2LiCl following by the oxidation of an intermediate cycloalkenyl lithium species using (Me3SiO)2 or (MeO) 3B/NaBO3·4H2O. (Chemical Equation Presented).
A new asymmetric synthesis of trans-hydroisoquinolones
Kamatani, Asayuki,Overman, Larry E.
, p. 1229 - 1232 (2007/10/03)
Matrix presented A convenient enantioselective synthesis of trans-hydroisoquinolones is described. This synthesis capitalizes on the ready availability of enantioenriched 2-substituted cyclohexenols by exploiting the asymmetry of an allylic carbon-oxygen
Stereoselective preparation of phosphine oxides via a 2,3-sigmatropic shift of allylic diphenylphosphinites
Demay, Stephane,Harms, Klaus,Knochel, Paul
, p. 4981 - 4984 (2007/10/03)
The thermic rearrangement of various chiral or racemic allylic diphenylphosphinites to allylic phosphine oxides has been applied for the preparation of several chiral diphosphine oxides of interest for asymmetric catalysis.
