5 research outputs found
Development of Enantioselective PalladiumâCatalyzed Alkene Carboalkoxylation Reactions for the Synthesis of Tetrahydrofurans
The Pdâcatalyzed coupling of Îłâhydroxyalkenes with aryl bromides affords enantiomerically enriched 2â(arylmethyl)tetrahydrofuran derivatives in good yield and up to 96:4 e.r. This transformation was achieved through the development of a new TADDOL/2âarylcyclohexanolâderived chiral phosphite ligand. The transformations are effective with an array of different aryl bromides, and can be used for the preparation of products bearing quaternary stereocenters.The construction of enantiomerically enriched tetrahydrofurans is accomplished by asymmetric Pdâcatalyzed crossâcoupling reactions between Îłâhydroxyalkenes and aryl bromides. Use of a palladium catalyst supported by a new TADDOLâderived chiral phosphite ligand provides the tetrahydrofuran products in good yield with up to 96:4 e.r. (see scheme).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/115961/1/anie_201506884_sm_miscellaneous_information.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/115961/2/13390_ftp.pd
Asymmetric PalladiumâCatalyzed Alkene Carboamination Reactions for the Synthesis of Cyclic Sulfamides
The synthesis of cyclic sulfamides by enantioselective Pdâcatalyzed alkene carboamination reactions between Nâallylsulfamides and aryl or alkenyl bromides is described. High levels of asymmetric induction (up to 95:5 e.r.) are achieved using a catalyst composed of [Pd2(dba)3] and (S)âSiphosâPE. Deuteriumâlabelling studies indicate the reactions proceed through synâaminopalladation of the alkene and suggest that the control of synâ versus antiâaminopalladation pathways is important for asymmetric induction.Aminate the double bond! The enantioselective Pdâcatalyzed coupling of aryl or alkenyl bromides with Nâallylsulfamides affords substituted cyclic sulfamides in good yield with high levels of asymmetric induction (see scheme). The reactions proceed through stereoselective synâaminopalladation of the alkene, which is important for high enantioselectivity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134229/1/chem201600887-sup-0001-misc_information.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134229/2/chem201600887.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134229/3/chem201600887_am.pd
Harnessing the ÎČâSilicon Effect for Regioselective and Stereoselective Rhodium(II)-Catalyzed CâH Functionalization by Donor/Acceptor Carbenes Derived from 1âSulfonyl-1,2,3-triazoles
The
regioselective and enantioselective intermolecular sp<sup>3</sup> CâH
functionalization of silicon-substituted alkanes was
accomplished using Rh<sub>2</sub>(<i>S-</i>NTTL)<sub>4</sub> with readily available 1-sulfonyl-1,2,3-triazoles as carbene precursors.
These reactions generate a diverse array of stereodefined substituted
silaalkanes
Synthesis of Cyclic Guanidines via Silver-Catalyzed Intramolecular Alkene Hydroamination Reactions of <i>N</i>âAllylguanidines
The silver-catalyzed
hydroamination of tosyl-protected <i>N</i>-allylguanidines
is described. These reactions provide
substituted cyclic guanidines in high yields. The reactions are amenable
to the construction of quaternary stereocenters as well as both monocyclic
and bicyclic guanidine products