Photocyclization reactions of substituted 2,2'-divinylbiphenyl derivatives

Synthesis of substituted pyrenes by indirect methods

“…110 Later, the strategy was successfully applied to the synthesis of several 4,9disubstituted THPy derivatives (Table 2). 111,112 The efficiency of the cyclisation was found to be dependent on the substituent on the vinyl group and the conditions used ( particularly λ).…”

Synthesis of 2‐ and 2,7‐Functionalized Pyrene Derivatives: An Application of Selective CH Borylation

“…Using these nominally nucleophilic and electrophilic derivatives as coupling partners in Suzuki-Miyaura, Sonogashira, and Buchwald-Hartwig cross-coupling reactions, we obtained 2,7-bis(R)-pyrenes with R = 16), and R = OTf, R' = C CTMS (13). Lithiation of 4, followed by reaction with CO 2 , yielded pyrene-2,7-dicarboxylic acid (17), whilst borylation of 2-tBu-pyrene gave 2-tBu-7-Bpin-pyrene (18) selectively. By similar routes (including Negishi cross-coupling reactions), monosubstituted 2-R-pyrenes with R = BF 3 K (19), Br (20), OH (21), B(OH) 2 (22), […”

“…Using these nominally nucleophilic and electrophilic derivatives as coupling partners in Suzuki-Miyaura, Sonogashira, and Buchwald-Hartwig cross-coupling reactions, we obtained 2,7-bis(R)-pyrenes with R = (4-CO 2 C 8 H 17 )C 6 H 4 (8), Ph (9), C CPh (10) 14), C CH (15), N(Ph)A C H T U N G T R E N N U N G [(4-OMe)C 6 H 4 ] ( 16), and R = OTf, R' = C CTMS (13). Lithiation of 4, followed by reaction with CO 2 , yielded pyrene-2,7-dicarboxylic acid (17), whilst borylation of 2-tBu-pyrene gave 2-tBu-7-Bpin-pyrene (18) selectively. By similar routes (including Negishi cross-coupling reactions), monosubstituted 2-R-pyrenes with R = BF 3 K (19), Br (20), OH (21), B(OH) 2 (22), [4- (24), OTf (25), C CPh (26), C CTMS (27), (4-CO 2 Me)C 6 H 4 (28), C CH (29), C 3 H 6 CO 2 Me (30), OC 3 H 6 CO 2 Me (31), C 3 H 6 CO 2 H (32), OC 3 H 6 CO 2 H (33), and OA C H T U N G T R E N N U N G (CH 2 ) 12 Br (34) were obtained from 2.…”

The Synthesis of Conjugated Bis-Aryl Vinyl Substrates and Their Photoelectrocyclization Reactions towards Phenanthrene Derivatives

“…As an example of the use of the oxidation of phenanthrenes to access cyclization precursors, Padwa carried out the ozonolysis of phenanthrene derivatives 3 to synthesize bis-2,2′-dialdehyde or ketones 4. 6 A subsequent Wittig reaction was used to deliver divinyl biaryl cyclization precursors 5 (Scheme 2).…”

“…Padwa and co-workers showed that a [1,5]-acyl shift could be used to rearomatize the electrocyclization intermediate (Scheme 25). The cyclization of vinyl biaryl 78 resulted in dihydrophenanthrenes 79 and 80 as a 3:1 mixture, respectively 6. It was interesting that the[1,5]-acyl shift was faster than the[1,5]-hydride shift in this system.Scheme 25 Photoelectrocyclizations and [1,5]-acyl shift 3E.4.…”