Organocatalytic Entry to Chiral Bicyclo[3.n.1]alkanones via Direct Asymmetric Intramolecular Aldolization
摘要:
The facile stereoselective syntheses of endo-8-hydroxybicyclo[3.3.1]nonan-2-one and endo-7-hydroxybicyclo[3.2.1]octan-2-one, featuring an alpha-amino acid catalyzed intramolecular aldolization of sigma-symmetric substrates, are described. A high enantioselectivity and a high catalytic efficiency have been exhibited by (4R,2S)-tetrabutylammonium 4-TBDPSoxy-prolinate in the aldolization of 3-(4-oxocyclohexyl)propionaidehyde to give highly enantiomerically enriched (1S,5R,8R)-8-hydroxybicyclo[3.3.1]nonan-2-one.
Methodology for <i>in Situ</i> Protection of Aldehydes and Ketones Using Trimethylsilyl Trifluoromethanesulfonate and Phosphines: Selective Alkylation and Reduction of Ketones, Esters, Amides, and Nitriles
ensuing reactions of other carbonyl moieties in the substrates liberates the aldehyde moiety, a sequence involving aldehydeprotection, transformation of other carbonyl groups, and deprotection can be accomplished in a one-pot manner. Furthermore, the use of PEt(3) instead of PPh(3) enables ketones to be converted in situ to their corresponding O,P-ketal type phosphonium salts and, consequently, selective
Step saver: Carbonyl groups with lower reactivities can be transformed in the presence of more reactive ones by treatment with PPh3 (or PEt3) and TMSOTf prior to the reaction (see scheme; TMS=trimethylsilyl, Tf=trifluoromethanesulfonyl). This methodology can be applied to reduction and alkylation reactions, and enabled the short asymmetric totalsynthesis of (+)‐centrolobine with the highest overall
the synthesis of both enantiomers of a functionalized bicyclo[3.2.1]octenone, which is potentially useful as a versatile chiral buildingblock, has been developed from 1,4-cyclohexanedione monoethylene acetal by employing proline-catalyzed diastereoselective intramolecular aldolization and lipase-mediated kinetic resolution as the key steps. The synthetic utility of the bicyclo[3.2.1]octenone has been
The first demonstration of a 100% atom-efficient selective reduction of less reactive ketones over aldehydes using heterogeneous catalysts is reported. Extremely high selectivities for intra- and intermolecular reductions of ketones over aldehydes were achieved. This system was also applicable to a column reactor, leading to a gram-scale synthesis.
NITROGEN-CONTAINING HETEROCYCLIC COMPOUNDS AND METHODS OF USE THEREOF
申请人:Palani Anandan
公开号:US20110152259A1
公开(公告)日:2011-06-23
The present invention provides compounds of Formula (I):
and pharmaceutically acceptable salts, solvates, esters, and tautomers thereof, wherein:
Q is selected from the group consisting of:
and
L is selected from the group consisting of:
pharmaceutically compositions comprising one or more compounds of formula (I), and methods of using the compounds of formula (I).