Ligand and counteranion enabled regiodivergent C–H bond functionalization of naphthols with α-aryl-α-diazoesters

Abstract

An unprecedented ligand- and counteranion-controlled and site-selectivity switchable direct C–H bond functionalization of unprotected naphthols with α-aryl-α-diazoesters was developed.

Regioselective Arene C−H Alkylation Enabled by Organic Photoredox Catalysis

“…In contrast to previous methods utilizing metallocarbene intermediates, this transformation does not proceed via a carbene intermediate, nor does it require the presence of a transitionmetal catalyst.Metallocarbenes are reactive organometallic species that may be generated by using a transition-metal precursor and diazoacetate derivatives. [1][2][3] The resulting carbene intermediate may then undergo CÀH insertion with reactive CÀH bonds (often aryl or alkyl), affording the corresponding alkylated adducts. However, owing to the high reactivity of metallocarbenes, aromatic substrates are often required to be present in excess for efficient reactivity.Among methodologies based on metallocarbene CÀH insertion that do not use a several-fold excess of arene, directing groups are often required.…”

“…Metallocarbenes are reactive organometallic species that may be generated by using a transition-metal precursor and diazoacetate derivatives. [1][2][3] The resulting carbene intermediate may then undergo CÀH insertion with reactive CÀH bonds (often aryl or alkyl), affording the corresponding alkylated adducts. However, owing to the high reactivity of metallocarbenes, aromatic substrates are often required to be present in excess for efficient reactivity.…”

Alkoxydiaminophosphine Ligands as Surrogates of NHCs in Copper Catalysis

“…EDA, NaBAr F 4 ,r eagents and substrates were purchased from Sigma-Aldrich and used without previous purification. The bromodiaminophosphine 1, [8] PhEDA [24] and MEDA [25] were prepared according to literature methods. Elemental analyses were performed on aP erki-nElmer Series II CHNS/O Analyzer 2400.…”

Organocatalytic Enantioselective Regiodivergent C−H Bond Functionalization of 1‐Naphthols with 1‐Azadienes

“…Recently, Liu and Zhang et al graciously reported a ligand and counteranion-controlled and site-selective switchable carbonÀ hydrogen bond functionalization of 1-naphthols with α-aryl-αdiazoesters (Scheme 1A). [14] Inspired by their nice work, we envisioned that the choice of suitable chiral organocatalyst and reaction partner might enable the establishment of enantioselective regiodivergent Friedel-Crafts reaction of unprotected 1-naphthols. Fully aware of both the potential benefits and the difficulties we would likely encounter, we decided to pursue this challenge.…”

“…Excitingly, the p-selective product 4 aa could be obtained in 99% yield with 88% ee from the CPA-4 mediated Michael addition of 1naphthol 1 a to 1-azadiene 2 a. Systematic screening of reaction parameters, including solvent ( Table 3, entries 5-9), temperature ( Table 3, entries 10-12), and concentration ( Table 3, entries [13][14] revealed that CPA-4 with a 1 mol% loading enabled the formation of p-selective product 4 aa in 99% yield with 88% ee.…”