DFT-Guided Phosphoric-Acid-Catalyzed Atroposelective Arene Functionalization of Nitrosonaphthalene

Chiral Phosphoric Acid: A Powerful Organocatalyst for the Asymmetric Synthesis of Heterocycles with Chiral Atropisomerism

“…To further extend the concept of organocatalytic asymmetric nucleophilic aromatic substitution, Tan et al . investigated a series of naphthalenes derivatives carrying substituents with electronic properties similar to those of the azo group with the assistance of electronic structure calculations [32] . The screening results shows that the nitroso group is another promising candidate for arene functionalization due to its significant decrease in LUMO energy through interactions with CPA.…”

“…electronic properties similar to those of the azo group with the assistance of electronic structure calculations. [32] The screening results shows that the nitroso group is another promising candidate for arene functionalization due to its significant decrease in LUMO energy through interactions with CPA. CPA16 proved to be superior for the cross-coupling reaction between 2-nitrosonaphthalenes 98 and indoles 51 and the oxidation products, namely the axially chiral indole-naphthalenes 100, were formed in 64-97 % yields and high to excellent enantioselectivities (91-99 % ee) when 99 was applied as the external oxidant.…”

A Versatile Method for Kinetic Resolution of Protecting‐Group‐Free BINAMs and NOBINs through Chiral Phosphoric Acid Catalyzed Triazane Formation

“…The List [11] and Kürti [12] groups reported the enantioselective synthesis of BINAMs via chiral Brønsted acid catalyzed asymmetric [3,3]‐sigmatropic rearrangement of biaryl hydrazines, respectively, albeit with limited scope. Recently, Tan and co‐workers developed a series of elegant asymmetric catalytic methods for asymmetric synthesis of BINAMs, NOBINs and their analogues via chiral Brønsted acid and Lewis acid catalyzed asymmetric additions of 2‐naphthols and 2‐naphthylamines with iminoquinones, [13] azonaphthalenes, [14] and nitrosonaphthalenes [15] …”

“…Recently, Tan and co-workers developed a series of elegant asymmetric catalytic methods for asymmetric synthesis of BINAMs, NOBINs and their analogues via chiral Brønsted acid and Lewis acid catalyzed asymmetric additions of 2-naphthols and 2-naphthylamines with iminoquinones, [13] azonaphthalenes, [14] and nitrosonaphthalenes. [15] The alternative strategy for asymmetric catalytic synthesis of BINAM and NOBIN derivatives is the kinetic resolution of their racemic substrates, which have also been proven fruitful. Tan and co-workers developed a highly efficient kinetic resolution of BINAM and its derivatives through asymmetric reductive aminations (Figure 1 a).…”

Kinetic Resolution of 2‐N‐Acylamido Tertiary Allylic Alcohols: Asymmetric Synthesis of Oxazolines

“…Recently, Ding and co-workers reported a highly efficient method for asymmetric catalytic synthesis of chiral cyclohexyl-fused SPINOLs via enantioselective hydrogenations, [21] which we envisioned would be an ideal starting material for asymmetric synthesis of novel SPAs. [22] With this idea in mind, we started our study by Suzuki coupling of the known cyclohexyl-fused SPINOL derivative 1 (99% ee) with MeB(OH) 2 , which was followed by deprotection of the OÀ Me groups and ortho-iodination to provide the di-iodinated product 2 with high efficiency (86% for 3 steps, Scheme 1). With this key intermediate 2 in hand, a range of aryl boronic acids were then coupled under Suzuki coupling conditions to give the corresponding diols, which were converted to Cy-SPAs A1-7 via phosphoration and subsequent hydrolysis.…”