Aminohalogenation of Electron‐Deficient Olefins Promoted by Hypervalent Iodine Compounds

Abstract

An efficient and practical procedure for the aminohalogenation of electron-deficient olefins promoted by hypervalent iodine compounds has been demonstrated. The catalytic efficiency of various hypervalent iodine compounds with different carboxylic and sulfonic ligands has also been investigated and of these (diacetoxyiodo)benzene exhibited the highest activity. A series of substrates, including α,β-unsatu-

Hypervalent Iodine (III) Catalyzed Regio- and Diastereoselective Aminochlorination of Tailored Electron Deficient Olefins via GAP Chemistry

“…Based on experimental observations and our as well as others' previous works (Li et al, 2001;Wei et al, 2001;Wang and Wu, 2007;Wu and Wang, 2008;Chen et al, 2009), a rational mechanism for the formation of 13 and 14 is illustrated in Scheme 6. 4-TsNCl 2 on reaction with 4-TsNH 2 may produce N-chloro-p-toluenesulfonamide (4-TsNHCl) 15, which might be oxidized by PhI OAc (Kikugawa et al, 2003;Murata et al, 2008) Typical procedure: Into a dry vial, 11 or 12 (1.5 mmol, 1 eq), 4-TsNCl 2 (3 mmol, 2 eq) 4-TsNH 2 (3 mmol, 2 eq), PhI(OAc) 2 (20 mol%), and freshly activated 4 Å molecular sieves (150 mg) were added.…”

“…Several research groups have made great contributions in developing both intermolecular and intramolecular aminohalogenation (Minakata et al, 2006 ; Li et al, 2007 ; Michael et al, 2008 ; Chen et al, 2010 ; Denmark et al, 2012 ; Yin et al, 2012 ; Chemler and Bovino, 2013 ; Song et al, 2013 , 2016 ; Martínez and Muñiz, 2014 ; Broggini et al, 2015 ; Qin et al, 2015 ; Zhu et al, 2015 ; Legnani et al, 2018 ; Cai et al, 2019 ), in which a series of halogen/nitrogen sources, such as CFBSA (Pu et al, 2016 ), NCS/MeCN (Tay et al, 2013 ), NCP (Zhu et al, 2018 ), NFSI/TMSCl (Arteaga et al, 2018 ), TsNCl 2 (Han et al, 2007 ; Wu and Wang, 2008 ; Wei et al, 2009 ), TsNHCl (Cai et al, 2011 ), TsNNaCl (Martínez and Muñiz, 2014 ), 2-NsNNaCl (Li et al, 2001 ), or the combination of 2-NsNCl 2 and 2-NsNHNa (Liu et al, 2006 ), and so on, were employed for many types of alkene substrates. Most of these aminohalogenation systems take advantage of metals or organic catalysts to give good yields and excellent regioselectivities and diastereoselectivities.…”

Highly Regio‐ and Stereoselective Synthesis of α‐(N‐Alkyl‐N‐p‐toluenesulfonyl)‐β‐Bromo‐Ketones via Ni(OAc)2‐Catalyzed Aminobromination of Chalcones

“…Initially, a readily available starting material chalcone ( 1a ) was subjected to the reaction under normal catalytic conditions (37–39). The reaction was carried out in dichloromethane by using CuI as the catalyst in the presence of 4 Å molecular sieves.…”

“…Although many synthetic approaches to vicinal haloamines have been developed using α,β‐unsaturated carbonyls as substrates (19–27), the development of highly regio‐ and stereoselective aminohalogenation still remains challenging. So far, several nitrogen/halogen resources for the aminohalogenation reaction have been developed including N,N‐ dichloro‐ p ‐toluenesulfonamide (TsNCl 2 ) (20–27), N,N ‐dibromo‐ p ‐toluenesulfonamide (TsNBr 2 ) (28–31), chloramine‐T (32–34), the combination of 2‐NsNCl 2 /2‐NsNHNa (2‐Ns = 2‐nitrobenzenesulfonyl) (35,36), and the combination of TsNH 2 and NBS (37–39). In the above‐known systems, there still exists shortcomings for α,β‐unsaturated ketones in regard to substrate scope (40) and stereoselectivity (41–48).…”

Approach to Vicinal t-Boc-amino Dibromides via Catalytic Aminobromination of Nitrostyrenes without Using Chromatography and Recrystallization

“…1-6 For example, they can be readily converted into many other synthetic precursors, such as aziridines and enamines. In the past one decade, many efforts have been devoted to this reaction under a series of metal-catalyzed and organocatalytic conditions.…”