Domino Cyclization of 1,n-Enynes (n = 7, 8, 9) Giving Derivatives of Pyrane, Chromene, Fluorene, Phenanthrene and Dibenzo[7]annulene by Ruthenium Complexes.

Cyclization of the ether enyne 1 catalyzed by [Ru]NCCH3(+) ([Ru] = Cp(PPh3)2Ru) in CHCl3 generates a diastereomeric mixture of the substituted tetrahydropyran 11. Presumably, formation of an allenylidene complex is followed by a cyclization by nucleophilic addition of the olefinic group to Cγ of the ligand giving a boat-like six-membered ring. The diastereoselectivity is controlled by the 1,3-diaxial interaction.

Instantaneous room-temperature and highly enantioselective ArTi(O-i-Pr)3 additions to aldehydes.

Direct asymmetric additions of ArTi(O-i-Pr)(3) to aldehydes catalyzed by a titanium catalyst of (R)-H(8)-BINOL are reported. The reactions proceed instantaneously at room temperature, affording alcohols in ≥90% ee. Importantly, the ArTi(O-i-Pr)(3) reagent differentiates the ligand effectiveness in an order of H(8)-BINOL > BINOL > TADDOL > diol 3 > disulfonamide 2.

Highly enantioselective 3-furylation of ketones using (3-furyl)titanium nucleophile.

A novel asymmetric 3-furyl addition of (3-furyl)Ti(O(i)Pr)(3) to ketones in the presence of 10 mol % (S)-BINOL is reported. The catalytic system works excellently for aromatic ketones, alpha- or beta-halophenones, alpha,beta-unsaturated ketones, and acetylfuran, affording products in high yields with excellent enantioselectivities of up to 97% ee.

Triphen-yl(tetra-hydro-furan)-aluminium(III).

In the title compound, [Al(C(6)H(5))(3)(C(4)H(8)O)], the Al atom has a distorted tetra-hedral geometry. The C-Al-C angles range from 113.25 (7) to 116.