Vitamin-B12-Catalyzed C,C-Bond Formation. Synthesis of a california red scale pheromone

✍ Scribed by Lucas Auer; Christophe Weymuth; Rolf Scheffold

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: German
• Weight: 595 KB
• Volume: 76
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19930760205

✦ Synopsis

8 a ) 1) 0 3 , MeOH, -78"; 2) Me2& MeOH, 0". b ) Li[AIH(t-BuO),], THF, -70°, 4 h; 52% yield from4. c ) DCC.Mel, THF, r.t., 22 h; 86% yield. d ) (CH20H)2, pyridinium toluene-4-sulfonate, C,H,, reflux, 5 h; 91 % yield.

cathode compartment of a H-type cell at -1.2 V (vs. SCE), containing 3, 0 . 2 ~ LiCIO,/ DMF, and Cbl(1) (obtained by previous electroreduction from hydroxo-Cbl(II1)hydrochloride), in such a rate that the color of the catholyte stayed brown-green (Cbl(1)). After the current had dropped to the back-ground value (consumption of ca. 1.4 F/1 equiv. of €9, the mixture was worked up. Two constitutionally different compounds 9 and 10 in a ratio of ca. 2: 1, each a ca. 1 :1 mixture of 2 diastereoisomers 9a, b and 10a, b (GC) were obtained in 90% combined yield with respect to 8 (Scheme 3). The isomers 10a, lob, and the mixture 9a, b of acyclic diastereoisomers were separated by HPLC.