Diastereoselective conjugate additions to pi-allylmolybdenum complexes: a stereocontrolled route to 3,4,5-trisubstituted gamma-butyrolactones

Relative hemilabilities of H2B(az)2 (az = pyrazolyl, dimethylpyrazolyl, methimazolyl) chelates in the complexes [M(η-C3H5)(CO)2{H2B(az)2}] (M = Mo, W)

The question of B–H–Mo hemilability in a range of dihydrobis(azolyl)borate scorpionate ligands is discussed with reference to η³-allyl complexes [Mo(η³-C₃H₅)(CO)₂{H₂B(az)₂}] [az = pyrazolyl (pz), dimethylpyrazolyl (pz*), mercaptoimidazolyl (mt)].

Total synthesis of cananginone C and structural revision of debilisone A

A short, convergent and general strategy for stereoselective total synthesis of biologically active α-substituted γ-hydroxymethyl γ-lactone based natural products cananginone C and debilisone A has been developed. The salient features of this synthesis include Cadiot-Chodkiewicz coupling, Evans allylation, Sharpless asymmetric dihydroxylation and γ-lactonization. The originally proposed structure of debilisone A has been revised.

A new reaction motif: "homo-S(N)2'-like" direct nucleophilic addition to neutral eta(3)-allylmolybdenum complexes. total synthesis of the antimalarial (+)-isofebrifugine

Charge neutral TpMo(CO)(2)(5-acyloxy-eta(3)-pyranyl) and TpMo(CO)(2)(5-acyloxy-eta(3)-pyridinyl) scaffolds undergo a novel intermolecular "homo-S(N)2'-like" reaction with a variety of carbon nucleophiles. Combined with an annulative demetalation, the homo-S(N)2'-like substitution/annulative demetalation sequence rapidly generates 2,7-dioxabicyclo[4.3.0]nonane and 2-aza-7-oxabicyclo[4.3.0]nonane frameworks in good to excellent yields with high enantiopurity. An enantiocontrolled total synthesis of the antimalarial alkaloid (+)-isofebrifugine was achieved utilizing this reaction cascade.

Practical, scalable, high-throughput approaches to eta3-pyranyl and eta3-pyridinyl organometallic enantiomeric scaffolds using the Achmatowicz reaction

A unified strategy for the high-throughput synthesis of multigram quantities of the eta(3)-oxopyranyl- and eta(3)-oxopyridinylmolybdenum complexes TpMo(CO)(2)(eta(3)-oxopyranyl) and TpMo(CO)(2)(eta(3)-oxopyridinyl) is described (Tp = hydridotrispyrazolylborato). The strategy uses the oxa- and aza-Achmatowicz reaction for the preparation of these organometallic enantiomeric scaffolds, in both racemic and high enantiopurity versions.

Efficient Synthesis of Novel γ-Substituted γ-Butenolides by Lewis Acid Catalyzed Addition of Metal Enolates of Active Methylene Compounds to Mucohalic Acids

Lewis acid catalyzed addition of active methylene compounds to mucochloric acid (1) and mucobromic acid (2) affording Knoevenagel aldol adducts, gamma-substituted gamma-butenolides, has been explored. Catalytic efficiencies of various Lewis acids have been compared. Indium acetate (0.25-5 mol %) was found to be the most efficient catalyst.