473292-85-2Relevant academic research and scientific papers
Convergent stereocontrol in Peterson olefinations. Application to the synthesis of (±)-3-hydroxybakuchiol and corylifolin
Perales, Joe B.,Makino, Narubumi F.,Van Vranken, David L.
, p. 6711 - 6717 (2007/10/03)
The iron-catalyzed Kirmse reaction was used to generate neopentyl α-silyl thioethers that were elaborated to meroterpenes using two complementary routes: one route involved a sila-Pummerer rearrangement, and the other route involved a Peterson olefination. While severe eclipsing interactions undermined the efficiency of the stereospecific sila-Pummerer rearrangement, they made it possible to stereoselectively generate E olefins without isolation or separation of syn- and anti-β-silyl alkoxides. Addition of a neopentyl α-silyl alkyllithium intermediate to an aryl aldehyde generated a mixture of syn- and anti-β-silyl alkoxides. The syn-β-silyl alkoxide eliminated stereospecifically at -78°C to give an E olefin, whereas the anti-β-silyl alkoxide was unreactive. The reaction mixture was then acidified and heated to induce stereospecific elimination of the anti isomer to give the same E olefin via a complementary cationic pathway. This route was used to complete the first synthesis of the meroterpene (±)-3-hydroxybakuchiol. In addition, we synthesized another meroterpene corresponding to the natural product corylifolin and offer evidence that the structure of corylifolin was misassigned.
