Polyols, which can be obtained readily from bio-feedstock, are converted efficiently into their corresponding cyclic carbonates by using a Wacker-type Pd/Mn catalyst system. A fine tuned redox cascade is essential in ensuring a high productivity of the Pd catalyst in the oxidative carbonylation reaction. Turnover numbers up to 784 mol_product/mol_palladium were achieved

Isostructural phosphine-phosphite ligands 7-10 have been synthesized from the condensation of chiral 3,3 0 -bis(trialkylsilyl)-2,2 0 -bisnaphthol phosphorochloridites and phenol-phosphanes 3-6. These ligands were evaluated as chiral inducers in the rhodium-catalyzed asymmetric hydroformylation reaction (AHF) of vinyl acetate and a series of styrene derivatives. The highest enantioselectivity, 78% ee, was observed in the AHF of vinyl acetate using phenylphosphino-based ligand 10. A direct correlation between the enantioselectivity and the Hammett constant σ of the substituent in the substrates was found (4-Me-styrene, 15% ee; styrene, 23% ee; 4-Cl-styrene, 51% ee) under mild reaction conditions for phenylphosphole-based ligand 8. Several rhodium-hydride and rhodium-acyl complexes were prepared and characterized by HP-NMR and HP-IR spectroscopy. Rhodiumhydride complexes of the formula [HRh(L)(CO) 2 ] A with ligands 7, 8, and 10 were found to be highly conformationally fluxional in solution. The reaction of 4-Cl-styrene with rhodium-hydride complexes of ligands 7 and 8 gave the corresponding rhodium-acyl derivatives [(RCO)Rh(CO) 2 (L)] E. A comparative analysis of the spectroscopic properties of these rhodium-acyl complexes revealed that [(RCO)Rh(CO) 2 ( 7)] was more conformationally labile than [(RCO)Rh(CO) 2 ( 8)].

The synthesis and resolution of chiral phenoxaphosphane 3, with the stereogenic center at the phosphorus atom, is described. Compound 3 has been synthesized following a wellknown procedure for trapping a phosphorus atom within a six-membered ring. The resolution of the racemic mixture of 3 was achieved through separation of its diastereomeric palladacycle derivatives 7a,b and 9a,b. The absolute configura-

The Prins reaction, an acid‐catalyzed condensation of alkenes with aldehydes, is used extensively in the fragrance industry. This year we celebrate the 100th anniversary of the discovery of this reaction. In honor of this occasion we present an overview of the diverse applications of the Prins reaction in the synthesis of flavor and fragrance ingredients. To pay tribute to the inventor of the Prins reaction, Hendrik Jacobus Prins, we also provide some insight into his life, scientific, and entrepreneurial accomplishments.

No abstract

The design of fragrances for laundry products which deliver a prolonged odor intensity at key consumer touch points is an ongoing challenge in the fragrance industry. Current fragrance development practices are based on the combination of perfumery expertise (eg creation of classic and modern odor themes such as Chypre or Fougère) with technical know‐how (eg chemical–physical properties of fragrance ingredients). However, due to the complexity of such multi‐component mixtures this process still requires a significant number of trial and error cycles throughout the fragrance development process to achieve the desired odor intensity and character requirements. To improve the efficiency of the fragrance development process, we have combined simple, high throughput analytical methods with psychophysical models, to predict the intensity and character of fragrances at three key consumer touch points for laundry products. The predicted results have shown a good agreement with experimental ones, making this approach useful in the early research phase for defining the structure/backbone of highly performing fragrance themes.

The Prins reaction, an acid‐catalyzed condensation of alkenes with aldehydes, is used extensively in the fragrance industry. This year we celebrate the 100th anniversary of the discovery of this reaction. In honor of this occasion we present an overview of the diverse applications of the Prins reaction in the synthesis of flavor and fragrance ingredients. To pay tribute to the inventor of the Prins reaction, Hendrik Jacobus Prins, we also provide some insight into his life, scientific, and entrepreneurial accomplishments.

No abstract