Indoles in multicomponent processes (MCPs).

2,5-Diketopiperazines: synthesis, reactions, medicinal chemistry, and bioactive natural products.

Stereocontrolled Domino Reactions

The term functionalized isocyanides refers to all those isocyanides in which a neighbouring functional group can finely tune the reactivity of the isocyano group or can be exploited in post-functionalization processes. In this manuscript, we have reviewed all the isocyanides in which the pendant functional group causes either deviation from or reinforces the normal reactivity of the isocyano group and categorized them to highlight their common features and differences. An analysis of their synthetic potential and the possible unexplored directions for future research studies is also addressed.

To each his own: isonitriles for all flavors. Functionalized isocyanides as valuable tools in organic synthesis

Quinazolinones, an important class of fused heterocyclic alkaloids has attracted high attention in organic and medicinal chemistry due to their significant and wide range of biological activities. There are approximately 150 naturally occurring quinazolinone alkaloids known till 2005. Several new quinazolinone alkaloids (∼55) have been isolated in the last decade. Natural quinazolinones with exotic structural features and remarkable biological activities have incited a lot of activities in the synthetic community towards the development of new synthetic strategies and approaches for the total synthesis of quinazolinone alkaloids. This review is focused on these advances in the chemistry of quinazolinone alkaloids in the last decade. This article covers the newly isolated quinazolinone natural products with their biological activities and the recently reported total syntheses of quinazolinone alkaloids from 2006 to 2015.

Recent developments in the chemistry of quinazolinone alkaloids

The first total synthesis of (−)-fructigenine A and a novel approach to (−)-5-N-acetylardeemin through a common imine intermediate (+)-3 are described. The key steps include highly enantioselective preparation of (+)-3 via domino olefination/isomerization/Claisen rearrangement (OIC) of 5, reductive cyclization (RC), and regioselective oxidation of (−)-4 and a novel assembly of the pyrazino ring of these alkaloids via Ugi three-component reaction/cyclization of (+)-3 with the corresponding amino acid and isonitrile.

Total syntheses of (-)-fructigenine A and (-)-5-N-acetylardeemin.

First total synthesis and stereochemical revision of okaramine M

Reduction of 3-cyanomethyloxindoles with lithium aluminum hydride at low temperature proceeded smoothly with cyclization to afford hexahydro-2-oxopyrrolo[2,3-b]indoles.

REDUCTIVE CYCLIZATION OF 3-CYANOMETHYLOXINDOLES TO HEXAHYDRO-2-OXOPYRROLO[2,3-b]INDOLES WITH LITHIUM ALUMINUM HYDRIDE

Reductive Cyclization of 3-Cyanomethyloxindoles to Hexahydro-2-oxopyrrolo[2,3-b]indoles with Lithium Aluminum Hydride.

Total synthesis of the proposed structure (I) reveals significant differences between the natural and the synthetic material.

Satoshi Takiguchi

Papers

Total syntheses of (-)-fructigenine A and (-)-5-N-acetylardeemin.

First total synthesis and stereochemical revision of okaramine M

REDUCTIVE CYCLIZATION OF 3-CYANOMETHYLOXINDOLES TO HEXAHYDRO-2-OXOPYRROLO[2,3-b]INDOLES WITH LITHIUM ALUMINUM HYDRIDE

Reductive Cyclization of 3-Cyanomethyloxindoles to Hexahydro-2-oxopyrrolo[2,3-b]indoles with Lithium Aluminum Hydride.

First Total Synthesis and Stereochemical Revision of Okaramine M.