A Diastereodivergent and Enantioselective Approach to syn- and anti-Diamines: Development of 2-Azatrienes for Cu-Catalyzed Reductive Couplings with Imines that Furnish Allylic Amines

We introduce a new reagent class, 2-azatrienes, as a platform for catalytic enantioselective synthesis of allylic amines. Herein, we demonstrate their promise by diasteredivergent and enantioselective synthesis of <i>syn</i>- and <i>anti</i>-1,2-diamines by Cu-bis(phosphine)-catalyzed reductive couplings with imines. With Ph-BPE, <i>anti</i>-diamines are obtained, and with the rarely utilized t-Bu-BDPP, <i>syn</i>-diamines are generated.<br>

A Diastereodivergent and Enantioselective Approach to syn- and anti-Diamines: Development of 2-Azatrienes for Cu-Catalyzed Reductive Couplings with Imines that Furnish Allylic Amines

We introduce a new reagent class, 2-azatrienes, as a platform for catalytic enantioselective synthesis of allylic amines. Herein, we demonstrate their promise by diasteredivergent and enantioselective synthesis of <i>syn</i>- and <i>anti</i>-1,2-diamines by Cu-bis(phosphine)-catalyzed reductive couplings with imines. With Ph-BPE, <i>anti</i>-diamines are obtained, and with the rarely utilized t-Bu-BDPP, <i>syn</i>-diamines are generated.<br>

P(OEt)3-Mediated Formal S–H Insertion: Reductive Couplings of Isatins with Thiols to Generate 3-Sulfenylated Oxindoles

A new P(OEt)3-mediated formal S–H bond-insertion reaction of isatins into thiols for the synthesis of valuable 3-sulfenylation oxindoles has been developed. This approach takes advantage of the unique reactivity of Kukhtin–Ramirez adducts to allow direct reductive S–H functionalization with commercially available and bench-stable starting materials.

2-Azadienes as Enamine Umpolung Synthons for the Preparation of Chiral Amines

The development of new strategies for the preparation of chiral amines is an important objective in organic synthesis. In this Synpacts, we summarize our approach for catalytically accessing nucleophilic aminoalkyl metal species from 2-azadienes, and its application in generating a number of important but elusive chiral amine scaffolds. Reductive couplings with ketones and imines afford 1,2-amino tertiary alcohols and 1,2-diamines, respectively, whereas fluoroarylations of gem-difluoro-2-azadienes deliver α-trifluoromethylated benzylic amines.1 Introduction2 Background: Umpolung Strategies for Preparing Chiral Amines3 Background: 2-Azadienes4 Reductive Couplings of 2-Azadienes5 Fluoroarylations of gem-Difluoro-2-azadienes6 Summary and Outlook

Cobalt bis(acetylacetonate)–tert-butyl hydroperoxide–triethylsilane: a general reagent combination for the Markovnikov-selective hydrofunctionalization of alkenes by hydrogen atom transfer

We show that cobalt bis(acetylacetonate) [Co(acac)2], tert-butyl hydroperoxide (TBHP), and triethylsilane (Et3SiH) constitute an inexpensive, general, and practical reagent combination to initiate a broad range of Markovnikov-selective alkene hydrofunctionalization reactions. These transformations are believed to proceed by cobalt-mediated hydrogen atom transfer (HAT) to the alkene substrate, followed by interception of the resulting alkyl radical intermediate with a SOMOphile. In addition, we report the first reductive couplings of unactivated alkenes and aryldiazonium salts by an HAT pathway. The simplicity and generality of the Co(acac)2–TBHP–Et3SiH reagent combination suggests it as a useful starting point to develop HAT reactions in complex settings.