Regioselective Formal [3+2] Cycloadditions of Urea Substrates with Activated and Unactivated Olefins for Intermolecular Olefin Aminooxygenation

Wu, Fan; Alom, Nur‐E; Ariyarathna, Jeewani Poornima; Naß, Johannes; Li, Wei

doi:10.1002/anie.201904662

Cited by 35 publications

(24 citation statements)

References 75 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…48 Next, a series of disubstituted alkenes were evaluated in our oxyimination conditions. Different symmetrical as well as unsymmetrical 1,2-disubstituted olefins gave their desired products in respectable yields (21)(22)(23)(24)(25)(26). In these cases, the regioselectivity of oxyimination was guided by the stability of the radical after the addition of the O-radical to the alkene.…”

Section: Reaction Scopementioning

confidence: 99%

See 1 more Smart Citation

Metal-free photosensitized oxyimination of unactivated alkenes with bifunctional oxime carbonates

et al. 2021

View full text Add to dashboard Cite

The 1,2-aminoalcohol motif is one of the most prevalent structural components found in high-value organic molecules including pharmaceuticals and natural products. Generally, their preparation requires pre-functionalised substrates and manipulations of one functional group at a time to achieve the desired regioisomer. Herein, we describe a metal-free photosensitisation protocol for the installation of both amine and alcohol functionalities into alkene feedstocks in a single step. This approach is enabled by the identification of oxime carbonate as a suitable bifunctional source of both oxygen-and nitrogen-centred radicals for addition across alkenes with complementary regioselectivity compared to Sharpless aminohydroxylation. Use of orthogonal protection for amine and alcohol functionalities enables direct synthetic diversifications of one functional handle without influencing the other. With the use of readily available starting materials, convergent synthesis and mild reaction conditions, this process is well suited for use in various synthetic endeavors.The vicinal aminoalcohol motif is one of the most abundant structural units in natural products, pharmaceuticals, agrochemicals and privileged ligands. [1][2][3] Synthetic routes to this motif rely typically on multistep, iterative manipulations of functional groups to introduce both amine and alcohol functionalities in their desired positions. [4][5][6] Usually transition metal-catalysed directed β-C-H functionalisation of alcohols or amines offers a synthetic alternative with the necessity of a preinstalled directing group. [7][8][9][10] Nevertheless, all these approaches involve manipulation of one functional group at a time (Fig. 1a). By comparison, aminohydroxylation of alkenes is the most straightforward yet powerful approach for the synthesis of 1-amino-2-alcohols allowing simultaneous introduction of both functionalities into the molecule in a single step, as pioneered by Sharpless. 11,12 The generality of this approach however is often plagued by poor regioselectivity and the need for N-haloamides. 13 The use of a similar concept to synthesise 2-amino-1-alcohol skeleton requires a complete regioselectivity switch and remains a challenge to date (Fig. 1b). 14,15 So far, transient N-centred radical initiated aminohydroxylation strategy has been exploited in different intramolecular cyclisation context through ingenious substrate design to generate 2-amino-1-alcohol framework. [16][17][18][19] Clearly, lack of substrate generality and intramolecular nature of these transformations obviates there widespread use. In this regard, Yoon has elegantly utilized high strain of oxaziridine ring in aminal synthesis with analogous regioselectivity. [20][21][22] However, the requirement for initial radical attack by the alkene substrate to the copper-activated oxaziridine limits the use of unactivated alkenes in this aminohydroxylation approach. Alternatively, a two-step aziridination of alkene followed by nucleophilic ring opening can also deliver a similar regiosel...

show abstract

Section: Reaction Scopementioning

confidence: 99%

“…Alternatively, a two-step aziridination of alkene followed by nucleophilic ring opening can also deliver a similar regioselective outcome. [23][24][25] However, low nucleophilicity of alcohols poses a significant challenge.…”

mentioning

confidence: 99%

Metal-free photosensitized oxyimination of unactivated alkenes with bifunctional oxime carbonates

et al. 2021

View full text Add to dashboard Cite

show abstract

“…With these observations in mind, our group is interested in the utilization of halonium as a catalytic and regiochemical template for intermolecular alkene oxyaminations to access nitrogencontaining heterocycles. 17 As documented in a recent literature, N-heterocycles are highly prevalent motifs in pharmaceuticals, natural products, and agrochemicals, which accounted for close to 60% of all the FDA approved small molecule drugs. 18 With respect to the research work here, a number of prominent bioactive molecules such as arabinose aminooxazoline, aminooxazoline xanthene, and allosamidin core, all contain an interesting 2-aminooxazoline framework (Scheme 3).…”

Section: Hypothesis Of Halonium As a Catalytic Templatementioning

confidence: 98%

Halonium Catalysis: An Underutilized and Underexplored Catalytic Concept in Olefin Functionalizations

Gembreska

Vogel²,

Ziegelmeyer³

et al. 2020

Synlett

Self Cite

View full text Add to dashboard Cite

show abstract

“…[33][34][35] Given these features, we wondered if the practical features of hypervalent iodine catalyst could be suited for the development of an efficient aza-Michael reaction. As part of our research interest in synthetic methods design to access useful nitrogen-containing compounds, [36][37][38][39][40][41][42][43][44] we disclose here a practical hypervalent iodine-catalyzed aza-Michael reaction with simple sulphonamides as the nitrogen nucleophile (Scheme 1c).…”

Section: Introductionmentioning

confidence: 99%

Hypervalent iodine-catalyzed conjugate addition with sulfonamides

Ariyarathna¹,

Ziegelmeyer²,

Li³

2021

Arkivoc

Self Cite

View full text Add to dashboard Cite

A hypervalent iodine-catalyzed conjugate addition with a sulfonamide nucleophile is described here. This reaction utilizes catalytic amounts of iodoarene and oxidant for the generation of the active hypervalent iodine catalyst. Activation of the enone substrate by the hypervalent iodine catalyst enables the nitrogen nucleophile addition that eventually forms a useful -aminocarbonyl product. This hypervalent iodinecatalyzed Aza-Michael reaction represents an interesting alternative to existing conjugate addition protocols.

show abstract

Regioselective Formal [3+2] Cycloadditions of Urea Substrates with Activated and Unactivated Olefins for Intermolecular Olefin Aminooxygenation

Cited by 35 publications

References 75 publications

Metal-free photosensitized oxyimination of unactivated alkenes with bifunctional oxime carbonates

Metal-free photosensitized oxyimination of unactivated alkenes with bifunctional oxime carbonates

Halonium Catalysis: An Underutilized and Underexplored Catalytic Concept in Olefin Functionalizations

Hypervalent iodine-catalyzed conjugate addition with sulfonamides

Contact Info

Product

Resources

About