[Ru(η5-C5H5)(η6-C10H8)]PF6 as a catalyst precursor for the one-pot direct C-H alkenylation of nitrogen heterocycles

TY - JOUR

T1 - [Ru(η5-C5H5)(η6-C10H8)]PF6 as a catalyst precursor for the one-pot direct C-H alkenylation of nitrogen heterocycles

AU - Lynam, J.M.

AU - Milner, L.M.

AU - Mistry, N.S.

AU - Slattery, J.M.

AU - Warrington, S.R.

AU - Whitwood, A.C.

PY - 2014/3/21

Y1 - 2014/3/21

N2 - The ruthenium naphthalene complex [Ru(η-CH )(η-CH)] is a catalyst precursor for the direct C-H alkenylation of pyridine and related nitrogen heterocycles by terminal alkynes. Stoichiometric studies have demonstrated that the naphthalene ligand may be displaced by either pyridine, 4-methylpyridine or dimethylaminopyridine (DMAP) to give species [Ru(η-CH)L] (L = nitrogen-based ligand). Reaction of in situ-generated [Ru(η- CH)(py)] (py = pyridine) with PPh results in the formation of [Ru(η-C H)(PPh)(py)], the active catalyst for direct alkenylation, some [Ru(η-C H)(PPh)(py)] is also formed in this reaction. A one-pot procedure is reported which has allowed for the nature of the nitrogen heterocycle and phosphine ligand to be evaluated. The sterically demanding phosphine PCy inhibits catalysis, and only trace amounts of product are formed when precursors containing a pentamethylcyclopentadienyl group were used. The greatest conversion was observed with PMe when used as co-ligand with [Ru(η- CH)(η-CH)] .

AB - The ruthenium naphthalene complex [Ru(η-CH )(η-CH)] is a catalyst precursor for the direct C-H alkenylation of pyridine and related nitrogen heterocycles by terminal alkynes. Stoichiometric studies have demonstrated that the naphthalene ligand may be displaced by either pyridine, 4-methylpyridine or dimethylaminopyridine (DMAP) to give species [Ru(η-CH)L] (L = nitrogen-based ligand). Reaction of in situ-generated [Ru(η- CH)(py)] (py = pyridine) with PPh results in the formation of [Ru(η-C H)(PPh)(py)], the active catalyst for direct alkenylation, some [Ru(η-C H)(PPh)(py)] is also formed in this reaction. A one-pot procedure is reported which has allowed for the nature of the nitrogen heterocycle and phosphine ligand to be evaluated. The sterically demanding phosphine PCy inhibits catalysis, and only trace amounts of product are formed when precursors containing a pentamethylcyclopentadienyl group were used. The greatest conversion was observed with PMe when used as co-ligand with [Ru(η- CH)(η-CH)] .

UR - http://www.scopus.com/inward/record.url?scp=84894501147&partnerID=8YFLogxK

U2 - 10.1039/c3dt52984c

DO - 10.1039/c3dt52984c

M3 - Article

AN - SCOPUS:84894501147

SN - 1477-9226

VL - 43

SP - 4565

EP - 4572

JO - Dalton Transactions

JF - Dalton Transactions

IS - 11

ER -