Ring-opening fluorination of bicyclic azaarenes

Abstract

We have discovered a ring-opening fluorination of bicyclic azaarenes. Upon treatment of bicyclic azaarenes such as pyrazolopyridines with electrophilic fluorinating agents, fluorination of the aromatic ring is followed by a...

N‐Fluoro Ammonium Salts of Cinchona Alkaloids in Enantioselective Electrophilic Fluorination

“…With the aid of stoichiometric amounts of (DHQD) 2 PHAL and Selectfluor or NFSI, this unprecedented reaction proceeded in moderate yields and ee values (Scheme 15). [49] …”

Catalytic alkene skeletal modification for the construction of fluorinated tertiary stereocenters

“… 8 Examples of this class of fluorinations that reach fluorinated tertiary stereocenters are limited to the catalytic cleavage of C(sp 3 )–C(sp 2 ) bonds of redox-active esters, 9 carboxylic acids, 10 and C(sp 3 )–C(sp 3 ) bonds in cyclopropanes. 11 However, to the best of our knowledge, synthesis of tertiary fluorinated stereocenters through catalytic alkene C(sp 2 )–C(sp 2 ) bond cleavage is previously unknown ( Fig. 1A ).…”

Ring-Opening Fluorination of Isoxazoles

“…Our group previously reported the first example of a ring-opening fluorination of heteroaromatic compounds (bicyclic azaarenes) such as pyrazolo­[1,5- a ]­pyridines (Figure B) . In this reaction, electrophilic fluorination of the C3 position proceeded to give a cationic intermediate.…”

“…Our group previously reported the first example of a ringopening fluorination of heteroaromatic compounds (bicyclic azaarenes) such as pyrazolo[1,5-a]pyridines (Figure 1B). 8 In this reaction, electrophilic fluorination of the C3 position proceeded to give a cationic intermediate. Subsequent deprotonation at the C2 position followed by N−N bond cleavage of the pyrazole moiety occurred to afford fluorocarbons with a C(sp 3 )−F bond.…”