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UV irradiation of the cycloheptadienyl complexes [(η 5 -C 7 H 8 R)Cr(CO) 3 SnPh 3 ] (1a, R ) H; 1b, R ) C(Me)S(CH 2 ) 3 S; 1c, R ) CHPh 2 ) or cyclohexadienyl complexes [(η 5 -C 6 H 6 R)Cr(CO) 2 -(NO)] (7, R ) C(Me)S(CH 2 ) 3 S) and 2 equiv of 2-butyne or 3-hexyne in toluene or n-hexane gave new tricyclic complexes 2, 5, and 8. These complexes arise from sequential [5 + 2] and homo[5 + 2] cycloadditions of two alkyne molecules to the η 5 -dienyl manifold forming 11-alkylidenetricyclo[5.3.1.0 4,10 ]undeca-2,5-diene or tricyclo[5.2.1.0 4,9 ]deca-2,5-dien-10-yl ligands, respectively. Heating 2 in acetonitrile gave [Cr(CO) 3 (CH 3 CN) 3 ] and the tricyclic organic compounds 3. UV irradiation of 1a and 1-phenyl-1-propyne or 1c and 2-butyne directly gave the organic compounds 4a,b and 5c, 6a,b, respectively, as mixtures of isomers. The adduct resulting from 1a and two molecules of 3-hexyne has been characterized by an X-ray diffraction study.

A concise bulk synthesis of stereochemically complex CCR2 antagonist BMS-741672 is reported. A distinct structural feature is the chiral all-cis 1,2,4-triaminocyclohexane (TACH) core, which was assembled through consecutive stereocontrolled heterogeneous hydrogenations: efficient Pt-catalyzed reduction of a β-enaminoester, directed by (S)-αmethylbenzylamine as a low-cost chiral template, and reductive amination of a 3,4-cis-disubstituted cyclohexanone over sulfided Pt/C introduced a tert-amine, setting the third stereocenter in the all-cis cyclohexane core. The heterogeneous catalysts were recycled. Ester hydrolysis produced a γ-amino acid, isolated as its Na salt. A challenging Curtius reaction to introduce the remaining C−N bond at C-2 was strongly influenced by the presence of the basic tert-amine, providing a stereoelectronically highly activated isocyanate. Detailed mechanistic and process knowledge was required to enable clean trapping with an alcohol (t-BuOH) while avoiding formation of side products, particularly an unusual carbamoyl phosphate. Deprotection, N-acetylation, and uncatalyzed S N Ar coupling with known 4-chloroquinazoline provided the final product. The resulting 12-step synthesis was used to prepare 50 kg of the target compound in an average yield of 82% per step.

UV irradiation of the cyclohexadienyl complex [(η5-C6H7)Mn(CO)3] (1) and 1 or 2 equiv of the alkynes PhC⋮CR (R = H, Me, Ph) in toluene gave both the [5 + 2] adducts [{η2: 3-C8H7Ph(R)}Mn(CO)3] (2) and the tricyclic [5 + 2],homo[5 + 2] double adducts [(η1:2:2-C10H7Ph2R2)Mn(CO)3] 3a−d. The reactions involve sequential metal-mediated alkyne cycloadditions, first across the η5-dienyl ligand and then across the resulting olefin−allyl manifolds. Reaction of the monoadducts 2 with an additional equivalent of 2-butyne or 1-phenyl-1-propyne gave the mixed double adducts 3e−j. The THF complex [(η5-C6H7)Mn(CO)2(THF)] (4) reacted thermally with 1-phenyl-1-propyne to form both types of adducts 2 and 3, indicating the role of UV light is to generate a coordinatively unsaturated metal center by CO ejection. Photolysis of 1 and dimethyl acetylenedicarboxylate gave the organic double adduct 1,2,3,10-tetrakis(methoxycarbonyl)tricyclo[5.2.1.04,9]deca-2,5-diene (5a), whereas protonation of 3a,c using HBF4·Et2O gave the analogous organic tricyclodienes 5b,c. Reaction of the adducts [(η1:2:2-C10H7R4)Mn(CO)3] (3a, 3k R = Me; 3l R = Et) with carbon monoxide (200 psi; 100 °C) gave new CO insertion products 6a−c. The single addition product 2c, the double adducts 3a and 3j, and the CO insertion products 6b,c have been characterized by X-ray diffraction studies.

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