Ruthenium-Catalyzed Cycloisomerizations of Diynols

Abstract

A wide variety of diynols containing tertiary, secondary, and primary propargylic alcohols undergo a cycloisomerization reaction to form dienones and dienals in the presence of a catalytic amount of [CpRu(CH(3)CN)(3)]PF(6). The formation of five- and six-membered rings is possible using this methodology. Secondary diynols react to form single geometrical isomeric dienones and -als. Primary diynols undergo a cycloisomerization as well as a hydrative cyclization process. The utility of primary diynol cycloisomerization is demonstrated in a synthesis of (+)-alpha-kainic acid.

Facile Ruthenium(IV)-Catalyzed Single and Double Allylation of Indole Compounds using Alcohols as Substrates: Aspects of Ruthenium(IV) Allyl Chemistry

“…1 H, 13 C, and 2D NMR spectra were recorded with Bruker DPX-250, 300, 400, 500, and 700 MHz spectrometers at room temperature. Chemical shifts are given in ppm and referenced to TMS for 1 H. Elemental analyses and mass spectroscopic studies were performed at ETHZ.…”

“…After the mixture was dried under vacuum, the crude product was again dissolved in acetone (5 mL), filtered through Celite, evaporated, and dried under vacuum to afford a brown solid (0.990 g, 94%). 1 [Ru(OAc)(η 3 -CH 2 CHCHCHdCH 2 )(Cp*)](PF 6 ) (13). 1,4-Pentadien-3-yl acetate (28.8 µL, 0.228 mmol) was added to a solution of [Ru(Cp*)(MeCN) 3 ](PF 6 ) (0.100 g, 0.198 mmol) in CH 2 Cl 2 (8 mL).…”

“…1,2 In addition to the olefin metathesis 3 reaction, one finds new catalytic applications in oxidation, 4 reduction, 5 and C-C bond making [6][7][8] chemistry. The recent literature has documented renewed interest in the use of allylic substrates in the synthesis of new C-C, 9 C-N, 10 and C-O 11,12 bonds.…”

Transition metals in organic synthesis: Highlights for the year 2005

“…A related ruthenium catalyzed cyclization of 1-hydroxy-2,7 (or 8)-diynes to give substituted five-or six-membered rings was developed and used in a synthesis of ␣-kainic acid (Eq. (274)) [1351].…”

Synthesis of Alkynyl‐Glycinols by Lewis Acid Catalyzed Propargylic Substitution of Bis‐Imidates

“…for 6h-6j; (f) 5b, KF, MeOH 50°C then PentCϵCBr or triisopropylsilyl (TIPS)CϵCBr, NH 2 OH·HCl, 20 mol-% CuCl, BuNH 2 , room temp. for 6k and 6l; (g) 5b, KF, MeOH 50°C then 10 mol-% CuI, 2 mol-% Pd(PPh 3 ) 4 , diethanolamine, vinyl bromide, THF, room temp. for 6m.…”