Aromatic Fluorine as a Versatile Control Element for the Construction of Molecules with Helical Chirality

The study of metal-free and palladium-catalysed synthesis of benzochromenes via direct C–H arylation using unactivated aryl benzyl ethers derived from essential oils as raw materials

“…First, and with the pre-set biphenyl core, the intramolecular S N 2 reaction between phenols and fluorinated scaffolds promoted the formation of the middle ring (Path A). 8 Second, the intramolecular Diels-Alder reaction, via a cascade pathway, between furan and unactivated alkenes under catalyst-free conditions resulted in the formation of the aromatic ring (Path B). 9 Finally, the C-C coupling, which can be subcategorized into: the intramolecular biaryl formation (C Ar -C Ar ), known as the Suzuki-Miyaura, Negishi, Heck, Kumada-Corriu and Hiyama cross-coupling, involves the use of organometallics (B, Sn, Si, Zn, Mg, etc.)…”

Assembly of an Axially Chiral Dynamic Redox System with a Perfluorobiphenyl Skeleton into Dumbbell‐ or Tripod‐type Electron Donors

“…TheS N Ar reactions of perfluorobiphenyl derivatives with nucleophiles proceed selectively at the 4-or 4,4'-positions. [13] Thus,w ed esigned (R ax )-or (S ax )-6 with an ethynyl group at the 4-position as av ersatile synthon to prepare the optically pure dyad-and triad-assemblies,s ince the ethynyl group could act as ac onnecting group under the various metalcatalyzed coupling conditions.T he reaction of rac-1 with ethynyltriisopropylsilane in the presence of NaHMDS followed by removal of the TIPS group by using TBAF gave rac-6 along with the disubstituted derivative (rac-7;S cheme 3). Selective substitution at the 4-or 4,4'-positions was confirmed by the X-ray analysis [20] of 4,4'-diethynyl derivative rac-7 ( Figure S3).…”

Assembly of an Axially Chiral Dynamic Redox System with a Perfluorobiphenyl Skeleton into Dumbbell‐ or Tripod‐type Electron Donors

“…[13] Thus,w ed esigned (R ax )-or (S ax )-6 with an ethynyl group at the 4-position as av ersatile synthon to prepare the optically pure dyad-and triad-assemblies,s ince the ethynyl group could act as ac onnecting group under the various metalcatalyzed coupling conditions.T he reaction of rac-1 with ethynyltriisopropylsilane in the presence of NaHMDS followed by removal of the TIPS group by using TBAF gave rac-6 along with the disubstituted derivative (rac-7;S cheme 3). [13] Thus,w ed esigned (R ax )-or (S ax )-6 with an ethynyl group at the 4-position as av ersatile synthon to prepare the optically pure dyad-and triad-assemblies,s ince the ethynyl group could act as ac onnecting group under the various metalcatalyzed coupling conditions.T he reaction of rac-1 with ethynyltriisopropylsilane in the presence of NaHMDS followed by removal of the TIPS group by using TBAF gave rac-6 along with the disubstituted derivative (rac-7;S cheme 3).…”

“…From as ynthetic viewpoint, the incorporation of aFarene skeleton is advantageous because of the high reactivity toward S N Ar functionalization [13] by nucleophiles such as acetylides.F urthermore,t he Fa toms at the 6,6'-positions could prevent rotation around the biphenyl axis in 1 to allow its optical resolution. Thus,d yrex donor (R ax )/(S ax )-1 could serve as aversatile chiral synthon for the production of larger assemblies containing multiple dyrex units,such as dumbbelltype dyads (R ax ,R ax )/(S ax ,S ax )-2d,p,m or at ripod-type triad (R ax ,R ax ,R ax )/(S ax ,S ax ,S ax )-3,through connection with the acetylene linkers (Scheme 2).…”