Stereoselective synthesis of β-sinensal via a π-allylnickel(II) complex
Abstract
A new π-allylnickel(II) complex, di-µ-bromo-bis(1–3-η-2-methyl-6-methyleneocta-2,7-dienyl)dinickel (5) was prepared by the reaction of bromomyrcene (7a) and (8a) with nickel tetracarbonyl in benzene. The reaction of the complex (5) with iodobenzene in dimethylformamide afforded 8-phenylmyrcene (10) in a high degree of stereoselectivity (E/Z= 85/15). The complex (5) reacted with the chloro-acetal (14), derived in three steps from isoprene, to give the acetal (15) which upon hydrolysis afforded β-sinensal (1) in high stereoselectivity (93%E).