Catalytic Synthesis of n-Alkyl Arenes through Alkyl Group Cross-Metathesis

Abstract

n-Alkyl arenes were prepared in a one-pot tandem dehydrogenation/olefin metathesis/hydrogenation sequence directly from alkanes and ethylbenzene. Excellent selectivity was observed when (tBuPCP)IrH[subscript 2] was paired with tungsten monoaryloxide pyrrolide complexes such as W(NAr)(C[subscript 3]H[subscript 6])(pyr)(OHIPT) (1a) [Ar = 2,6-i-Pr[subscript 2]C[subscript 6]H[subscript 3]; pyr = pyrrolide; OHIPT = 2,6-(2,4,6-i-Pr[subscript 3]C[subscript 6]H[subscript 2])[subscript 2]C[subscript 6]H[subscript 3]O]. Complex 1a was also especially active in n-octane self-metathesis, providing the highest product concentrations reported to date. The thermal stability of selected olefin metathesis catalysts allowed elevated temperatures and extended reaction times to be employed.