Synthesis of aromatic bisabolene natural products via palladium-catalyzed cross-couplings of organozinc reagents.
Aromatic bisabolene derivatives were prepared by two methods involving cross-coupling of organozinc reagents. The first synthesis of (+/-)-glandulone A (10), as well as syntheses of (+/-)-curcuhydroquinone (8) and (+/-)-curcuquinone (9), were accomplished via coupling of a secondary alkyl zinc reagent (1,5-dimethyl-4-hexenylzinc halide, 18) to protected bromohydroquinones using Pd(dppf)Cl(2) as catalyst. Coupling of arylzinc halides with alkenyl triflate 16 using Pd(PPh(3))(4) catalyst provided a number of bisabolene derivatives and led to syntheses of dehydro-alpha-curcumene (2), (+/-)-curcuphenol (3), and (+/-)-elvirol (13). A high-yield synthesis of the (+/-)-heliannuol D precursor 29 is also reported using this method.
Vyvyan
James R
JR
Department of Chemistry, Western Washington University, Bellingham, Washington 98225-9150, USA. vyvyan@chem.wwu.edu
Loitz
Celeste
C
Looper
Ryan E
RE
Mattingly
Cheryl S
CS
Peterson
Emily A
EA
Staben
Steven T
ST
D001688:Biological Products / Q000138:chemical synthesis*; D002384:Catalysis; D007202:Indicators and Reagents; D010165:Palladium / Q000737:chemistry*; D012717:Sesquiterpenes / Q000138:chemical synthesis*; D013237:Stereoisomerism; D015032:Zinc / Q000737:chemistry*
D001688:Biological Products; D007202:Indicators and Reagents; D012717:Sesquiterpenes; C486063:glandulone A; D010165:Palladium; D015032:Zinc