An Efficient Approach to Chiral Allyloxyamines by Stereospecific Allylation of Nitrosoarenes with Chiral Allylboronates

Abstract

A novel and efficient approach to allyloxyamines by the allylation of nitrosoarenes with α-chiral allylboronates is described. C-O bond formation occurs with high stereospecificity and the product allyloxyamines are easily transformed into valuable chiral building blocks such as isoxazolidines and allylic alcohols. The reaction features complete regioselectivity (O-selectivity), high E/Z selectivity, and excellent chirality transfer.

Molecular mechanism of azoxy bond formation for azoxymycins biosynthesis

“…However, the nitroso-producing activity of non-heme diiron N -oxygenase has not yet been reported. In HEDM and other nitrogen-containing heterocycle synthesis, nitroso groups have better chemical activities than nitro, and they can act as both nucleophilic and electrophilic reagent to easily install nitrogen and oxygen atom complex structures 23–26 , such as imidaze 27 , benzimidazole 28 , triazole 29 , tetrazine 30 , and azabicycle 31 , all of which are synthetic intermediates in HEDM. Moreover, nitroso groups are good starting synthons in the synthesis of diazo, azo, and azoxy bond, which are efficient enhancers to significantly increase the energy level and thermal stability of HEDM 1 .…”

Synthesis and Utility of Dihydropyridine Boronic Esters

“…Thus,addition to benzaldehyde afforded the desired homoallylic alcohols (AE)-74-78 stereoselectively.A lternatively,o xidation of the boronic esters with sodium perborate gave the corresponding 6 ]/ NaBH 4 generated the enamide (AE)-85 with very high diastereoselectivity. [21] X-ray crystallography confirmed the surprising observation that [Mo(CO) 6 ]/NaBH 4 isomerized the olefin to form the conjugated (AE)-85. [22] Alternatively,hydrogenation with Pd/C gave the tetrasubstituted piperidine (AE)-86 with ad .r.…”

“…Theo bservation that the 2-chloropyridine was as uitable substrate is particularly noteworthy since these reagents readily participate in cross-coupling reactions.T hus their successful application highlights the mildness of the method while retaining the 2-chloro group for subsequent chemistry.T his reaction was also applied to quinoline 4-boronic esters,g iving good yields for these substrates (21,36,48). Expansion of this methodology to 5-and 7-borono-quinolines and 6-borono-isoquinoline was only modestly successful (49-51).…”

Advanced Nitroso Aldol Reaction: Metal-Free Cross-Coupling of Anilines with Silyl Enol Ethers en Route to α-Amino Ketones

“…One important route is the nitroso aldol reaction pioneered by Yamamoto, Miller, Read de Alaniz, Studer, and other groups. − Despite the great advancements made in terms of reactivity, selectivity, and substrate scope, the nitroso aldol reaction is underdeveloped from a green chemistry perspective . A central limitation of the α-amination of ketones via nitroso aldol reaction is that the overall transformation currently requires three discrete steps: synthesis/generation of nitroso compound, construction of the C–N bond, and cleavage of the N–O bond (Scheme a).…”

“…Furthermore, after the completion of the nitroso aldol reaction, the N–O bond must be cleaved to provide the α-amino ketone, leading to additional steps and reagents. Common methods for N–O bond cleavage include hydrogenolysis and stoichiometric metal reductions, which are often toxic and have compromised functional group compatibility. , Therefore, development of efficient, step-economical, and environmentally benign nitroso aldol reactions en route to α-amino ketones is highly desirable.…”