The [RhCl(CO)dppp](2)-catalyzed intramolecular carbonylative [2 + 2 + 1] cycloaddition of allenenes was developed to prepare bicyclo[4.3.0]nonenones possessing a methyl group at the ring junction, which is difficult to achieve by the Pauson-Khand reaction of the corresponding enynes. This method also provided a new procedure for the construction of the tricyclo[6.4.0.0(1,5)]dodecenone framework...

The bicyclo-[3.3.1]nonane ring in the title compound, C(39)H(44)N(2)O, adopts a chair-boat conformation with the four benzene rings being directed away from the carbonyl group. The presence of C-H⋯O contacts leads to helical supra-molecular chains along the b axis.

Phosphine catalyzed enantioselective [3+2] cyclizations on 4-substituted 2,6-diarylidenecyclohexanones and 2,4-diarylidene-bicyclo[3.1.0]hexan-3-ones take place with high diastereo- and enantioselectivity levels. The process affords spirocyclic compounds with excellent stereochemical control of up to five stereogenic centres.

The total synthesis of sculponeatin N, a bioactive polycyclic diterpene isolated from Isodon sculponeatus, is reported. Key features of the synthesis include diastereoselective Nazarov and ring-closing metathesis reactions, and a highly efficient formation of the bicyclo[3.2.1]octane ring system by a reductive radical cyclization.

An organocatalytic cascade reaction of 2-nitrocyclohexanone and α,β-unsaturated aldehydes was developed. Bicyclo[3.3.1]nonanone products were obtained with good yields and excellent enantioselectivities. The reaction occurred with unusual regioselectivity. A dienolate-iminium activation mechanism was proposed. The products were transformed to eight-membered cyclic ketones with high enantioselec...

A palladium-catalyzed intermolecular vicinal diarylation of terminal 1,3-dienes using aryldiazonium tetrafluoroborates and arylboronic acids is reported. Using this technology, two different arenes are regioselectively introduced in a vicinal fashion across the terminal alkene of a variety of terminal 1,3-dienes at ambient temperature. Through the action of a chiral bicyclo[2.2.2]octadienyl lig...

In the title compound, C(18)H(24)O(4)S, the chiral bicyclo-[2.2.1]heptane group is not symmetrical due to the influence of the substituents. The angle between the three-atom bridge plane and the four-atom planes of the boat-shaped six-membered ring are 55.07 (19) and 56.24 (19)°. The bridgehead angle is 92.75 (17)°.

A concise and scalable synthesis of a cis-fused bicyclo[5.3.0]decane ring system has been developed for the total synthesis of echinopines. The core of the natural products was constructed efficiently through an intramolecular 1,3-dipolar cycloaddition and ring contraction strategy.