Enantioselective Synthesis of the C(1)-C(6’) Subunit of Zaragozic Acid C

Abstract

A preparação da subunidade C(1)-C(6') do ácido zaragózigo é descrita. O estereocentro C(5'), contendo uma metila, é instalado através de uma abertura rápida e estereosseletiva de um fenilciclopropil carbinol utilizando o catalisador de Pearlman (1atmosfera de H2) em metanol contendo 2% de ácido trífilico. Preparation of the C(1)-C(6') subunit of Zaragozic acid C is described. The C(5') methyl-bearing stereocenter is installed by rapid, regioselective opening of a phenylcyclopropyl carbinol with Pearlman's catalyst (1 atm H2) in 2% triflic acid/methanol.

Creating Stereocenters within Acyclic Systems by C–C Bond Cleavage of Cyclopropanes

“…Similarly, for more substituted cyclopropyl species, the hydrogenolysis proceeds at the activated benzylic ( 5 → 6 ) and homobenzylic ( 7 → 8 ) carbon centers with very high selectivities (Scheme ). This rather simple strategy has been used for the selective preparation of the lateral C 1′ –C 6′ chain of zaragozic acid C . Catalytic hydrogenolysis of easily accessible enantiomerically enriched 9 afforded the key linear fragment 10 , which was subsequently transformed into the desired subunit of the natural product.…”

Natural Products Synthesis: A Personal Retrospective and Outlook

“…I have never believed that the end justifies the means in such an endeavor, and it is over the course of the crafting an innovative, successful route that the best science is accomplished. Molecules as complex as the zaragozic acids inevitably lead to unexpected surprises, new methods, and strategies ,. Indeed, over the many years following the initial work, the structure continues to attract interest by young investigators, who crafted highly creative approaches that amalgamate novel strategies with new methods development …”