Synthesis, molecular structure and fluxional behavior of (R)-7-p-tolyldinaphtho[2,1-b;1′,2′-d]stibole: the first isolated example of optically active group 15 dinaphthoheteroles

✍ Scribed by Shuji Yasuike; Tomoyasu Iida; Kentaro Yamaguchi; Hiroko Seki; Jyoji Kurita

• Publisher: Elsevier Science
• Year: 2001
• Tongue: French
• Weight: 106 KB
• Volume: 42
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)01977-8

✦ Synopsis

The condensation of dibromo-p-tolylstibane with 2,2%-dilithio-1,1%-binaphthyl 3, generated in situ from optically active 2,2%-dibromo-1,1%-binaphthyl (R)-(+)-2 by treatment with tert-butyllithium, afforded optically active (R)-( -)-7-p-tolyldinaphtho[2,1-b;1%,2%-d]stibole 1c, which is fluxional in the NMR time scale at elevated temperatures. The energy barrier (DG ‡ ) resulting from the flipping of the two naphthalene rings was estimated to be 85 ± 1 kJ mol -1 and its half life (t 1/2 ) for racemization was determined to be 5.2 h in benzene at 20°C.