René Liedtke, R. Fröhlich, G. Kehr
Sep 12, 2011
Citations
0
Influential Citations
41
Citations
Journal
Organometallics
Abstract
Tris(pentafluorophenyl)borane reacts with 9,9-dipropargylfluorene (5) in a 2:1 ratio under ambient conditions to yield a statistical mixture of the double-1,1-carboboration products (Z,Z)-, (E,Z)-, and (E,E)-6. Photolysis of the product mixture yields a new mixture that is substantially enriched in the (Z,Z)-6 isomer. Treatment of 5 with the P(o-tolyl)3/B(C6F5)3 frustrated Lewis pair gave the zwitterionic eight-membered heterocycle 7a, which is the product of a 1,1-carboboration of one alkynyl unit followed by an intramolecular 1,2-addition of the in situ generated new FLP to the remaining alkynyl moiety. The reaction of the PtBu3/B(C6F5)3 FLP gave an analogous result, yielding 7b. Treatment of 1,2-diethynylbenzene (9) with the PtBu3/B(C6F5)3 FLP resulted in deprotonation, forming the phosphonium/alkynylborate salt 10. The reaction of triarylphosphine/B(C6F5)3 pairs using the phosphines P(o-tolyl)3 and P{Ph2[2,5-bis(trifluoromethyl)phenyl]} resulted in clean 1,2-P/B FLP additions to a C≡C triple bond to y...