Enantioselective Syntheses of Bicyclic Lactams Based on Iridium-Catalyzed Asymmetric Allylic Substitution and Heck Cyclization

Acyclic Twisted Amides

In this contribution, we provide a comprehensive overview of acyclic twisted amides, covering the literature since 1993 (the year of the first recognized report on acyclic twisted amides) through June 2020. The review focuses on classes of acyclic twisted amides and their key structural properties, such as amide bond twist and nitrogen pyramidalization, which are primarily responsible for disrupting n_N to π*_C═O conjugation. Through discussing acyclic twisted amides in comparison with the classic bridged lactams and conformationally restricted cyclic fused amides, the reader is provided with an overview of amidic distortion that results in novel conformational features of acyclic amides that can be exploited in various fields of chemistry ranging from organic synthesis and polymers to biochemistry and structural chemistry and the current position of acyclic twisted amides in modern chemistry.

Chemistry of Bridged Lactams: Recent Developments

Bridged lactams represent the most effective and wide-ranging method of constraining the amide bond in a non-planar conformation. A previous comprehensive review on this topic was published in 2013 (Chem. Rev.2013, 113, 5701–5765). In the present review, which is published as a part of the Special Issue on Amide Bond Activation, we present an overview of the recent developments in the field of bridged lactams that have taken place in the last five years and present a critical assessment of the current status of bridged lactams in synthetic and physical organic chemistry. This review covers the period from 2014 until the end of 2018 and is intended as an update to Chem. Rev.2013, 113, 5701–5765. In addition to bridged lactams, the review covers recent advances in the chemistry of bridged sultams, bridged enamines and related non-planar structures.

Iridium-Catalyzed Asymmetric Allylic Substitution Reactions

In this review, we summarize the origin and advancements of iridium-catalyzed asymmetric allylic substitution reactions during the past two decades. Since the first report in 1997, Ir-catalyzed asymmetric allylic substitution reactions have attracted intense attention due to their exceptionally high regio- and enantioselectivities. Ir-catalyzed asymmetric allylic substitution reactions have been significantly developed in recent years in many respects, including ligand development, mechanistic understanding, substrate scope, and application in the synthesis of complex functional molecules. In this review, an explicit outline of ligands, mechanism, scope of nucleophiles, and applications is presented.