Disclosed herein is enantioselective synthetic method comprising reacting an enolisable C
4
-C
50
organic anhydride with a second compound selected from the group consisting of an aldehyde, a ketone, an aldimine, a ketimine or a Michael Acceptor in the presence of a bifunctional organocatalyst. The reaction may find particular utility in the enantioselective synthesis of medicinally relevant heterocycles, such as dihydroisocoumarins and dihydroisoquinolinones.
The present invention provides a compound of Formula (I)
or a pharmaceutically salt thereof wherein R
1
, R
2
, Ra, L, Z, Z
1
and Z
2
are as defined herein, that act as Ghrelin antagonists or inverse agonists; pharmaceutical compositions thereof; and methods of treating diseases, disorders, or conditions mediated by the antagonism of the Ghrelin receptor.
A fundamentally newreagent space has been discovered for the Castagnoli-Cushman reaction. Cyclic anhydride has been successfully replaced with CDI-activated monoesters of homophthalic acid allowing direct preparation of tetrahydroisoquinolonic esters. Mechanistic studies suggested a new reaction pathway not involving any previously described alkoxyisocoumarines.
Diastereo- and Enantioselective Construction of Dihydroisocoumarin-Based Spirooxindole Frameworks <i>via</i>
Organocatalytic Tandem Reactions
作者:Jia-Le Wu、Bai-Xiang Du、Yu-Chen Zhang、Ying-Ying He、Jing-Yi Wang、Ping Wu、Feng Shi
DOI:10.1002/adsc.201600271
日期:2016.9.1
An organocatalyticasymmetric approach has been developed for the ennantioselective construction of dihydroisocoumarin‐based spirooxindole frameworks in high yields, excellent diastereo‐ and enantioselectivities (up to 99%, all >95:5 dr, up to 99% ee). This approach takes advantage of chiral thiourea‐tertiaryamine catalyzed tandemreaction of isatins with enolizable homophthalic anhydride, which has
the expected carbocycles. This reaction is very similar in appearance to the classic 1,2-addition of cyclic anhydrides to imines, often referred to as the Castagnoli–Cushman reaction, but differs in mechanistic details (representing a 1,4-reaction of imine). The developed atom-economical, stereoselective and catalyst- and chromatography-free protocol provided facile access to 28 structurally diverse heterocyclic