Enantioselective Vinylogous Organocascade Reactions

Abstract

Cascade reactions are powerful tools for rapidly assembling complex molecular architectures from readily available starting materials in a single synthetic operation. Their marriage with asymmetric organocatalysis has led to the development of novel techniques, which are now recognized as reliable strategies for the one-pot enantioselective synthesis of stereochemically dense molecules. In recent years, even more complex synthetic challenges have been addressed by applying the principle of vinylogy to the realm of organocascade catalysis. The key to success of vinylogous organocascade reactions is the unique ability of the chiral organocatalyst to transfer reactivity to a distal position without losing control on the stereo-determining events. This approach has greatly expanded the synthetic horizons of the field by providing the possibility of forging multiple stereocenters in remote positions from the catalyst's point of action with high selectivity while simultaneously constructing multiple new bonds. This article critically describes the developments achieved in the field of enantioselective vinylogous organocascade reactions, charting the ideas, the conceptual advances, and the milestone reactions that have been essential for reaching highly practical levels of synthetic efficiency.

Recent Progress in Organocatalytic Asymmetric Domino Transformations

“…Ever since Barbas and co‐worker reported the first example of an organocatalytic asymmetric domino Michael/aldol reaction in 2000, such organocatalytic domino reactions have been undergoing explosive developments in the last two decades, as witnessed by the numerous review articles dedicated to this topic that have appeared in the past few years . However, due to the extremely fast growth in organocatalyzed domino reactions, many new developments keep showing up on a daily basis, which makes these reviews somewhat outdated very quickly.…”

“…However, due to the extremely fast growth in organocatalyzed domino reactions, many new developments keep showing up on a daily basis, which makes these reviews somewhat outdated very quickly. In addition, many of recently published review articles on this topic are quite narrow in terms of their scope, focusing on either the synthesis of specific scaffolds or the processes mediated by a specific type of organocatalyst . Due to the importance of this research and the fast developments in this area, we believe a new review is needed and, in the present review, we are going to summarize the most recent developments in organocatalyzed asymmetric domino reactions, covering the literature published from the beginning of 2012 up to May, 2017.…”

Stereoselective organocascades: from fundamentals to recent developments

“…Vinylgous versions of this cascade have been reported as well, setting remote stereocenters. Key to the success of this strategy is the identification of well suited substrates, characterized by the needed substitution pattern [22]. The first example was published by Tian and Melchiorre employing dienones and 3-substituted oxindoles.…”

Novel Methodologies for Chemical Activation in Organic Synthesis under Solvent-Free Reaction Conditions

“…Presently, organocatalysis continues to be a rapidly developing research area, as shown by the large number of publications that have appeared since 2000 [36]. Some recent examples are highlighted in references [37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56].…”