Synthetic Studies on Quassinoids: Total Synthesis and Biological Evaluation of (+)-Des-D-chaparrinone.
A total synthesis of des-D-chaparrinone (2), which lacks the ring D delta-lactone of (-)-chaparrinone (1) has been developed. The synthesis commences with the known, readily available tricyclic ketone 3 (R = Me). Elaboration of the configuration at C(5) followed by resolution of 6 employing 2(R),3(R)-2,3-butanediol gave rise to 9. Installation of the ring C functionality provided 15 which was transformed into tricyclic diketone 25. Introduction of the ring A functional groups afforded 29, which upon exposure to aluminum trichloride and sodium iodide gave rise directly to (+)-des-D-chaparrinone (2). Biological studies revealed that (+)-2 was devoid of any solid tumor activity.
Grieco
Paul A.
PA
Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717 and Department of Chemistry, Indiana University, Bloomington, Indiana 47405.
Speake
Jason D.
JD