Oxidative thiocyanation of allylic alcohols: an easy access to allylic thiocyanate within K2S2O8 and NH4SCN

A practical method for the synthesis of allylic thioacyanate from allylic alcohol was disclosed employing K2S2O8 as the oxidant and NH4SCN as the thiocyanate source. Without introducing a leaving group...

Laccase-Catalyzed Oxidation of Allylbenzene Derivatives: Towards a Green Equivalent of Ozonolysis

Laccase-based biocatalytic reactions have been tested with and without mediators and optimized in the oxidation of allylbenzene derivatives, such as methyl eugenol taken as a model substrate. The reaction primarily consisted in the hydroxylation of the propenyl side chain, either upon isomerization of the double bond or not. Two pathways were then observed; oxidation of both allylic alcohol intermediates could either lead to the corresponding α,β-unsaturated carbonyl compound, or the corresponding benzaldehyde derivative by oxidative cleavage. Such a process constitutes a green equivalent of ozonolysis or other dangerous or waste-generating oxidation reactions. The conversion rate was sensitive to the substitution patterns of the benzenic ring and subsequent electronic effects.

Greener Synthesis of Pristane by Flow Dehydrative Hydrogenation of Allylic Alcohol Using a Packed-Bed Reactor Charged by Pd/C as a Single Catalyst

Our previous work established a continuous-flow synthesis of pristane, which is a saturated branched alkane obtained from a Basking Shark. The dehydration of an allylic alcohol that is the key to a tetraene was carried out using a packed-bed reactor charged by an acid–silica catalyst (HO-SAS) and flow hydrogenation using molecular hydrogen via a Pd/C catalyst followed. The present work relies on the additional propensity of Pd/C to serve as an acid catalyst, which allows us to perform a flow synthesis of pristane from the aforementioned key allylic alcohol in the presence of molecular hydrogen using Pd/C as a single catalyst, which is applied to both dehydration and hydrogenation. The present one-column-two-reaction-flow system could eliminate the use of an acid catalyst such as HO-SAS and lead to a significant simplification of the production process.

(2R,4S,5S)-5-Methoxy-4-methyl-3-oxohept-6-en-2-yl benzoate

The title compound, C16H20O4, was synthesized in the course of the total synthesis of fusaequisin A in order to verify and confirm the configurations of the stereogenic centers and to exclude the possibility of epimerization during the methylation process. The crystal structure of the title compound at 100 K has orthorhombic (P212121) symmetry. The absolute configuration was determined by anomalous dispersion and agrees with the configuration of the allylic alcohol used in the synthesis.

Ruthenium-catalyzed Asymmetric Dehydrative Allylic Cyclization of Chalcogen 5-Membered Heteroaromatics

The asymmetric dehydrative intramolecular allylation reactions of furan and thiophene were performed using a cationic cyclopentadienyl-ruthenium (CpRu) complex of a chiral pyridine carboxylic acid, namely Cl-Naph-PyCOOH. Both furan and thiophene tethered with an allylic alcohol gave the corresponding bicyclic compounds in high yields and enantioselectivities using 0.1–5 mol% of catalyst. The reaction was found to proceed via a similar enantioface selection method mechanism to that previously reported by our group, which involved halogen and hydrogen bond formation, in addition to the generation of an intermediate σ-allyl complex.

Allylic Alcohol Synthesis by Ni-Catalyzed Direct and Selective Coupling of Alkynes and Methanol

Methanol is an abundant and renewable chemical raw material, but its use as a C1 source in C-C bond coupling reaction still constitutes a big challenge, and the known methods...

Cyanoalkylation/alkynylation of allylic alcohol through intramolecular radical 1,2-alkynyl migration

A di-tert-butyl peroxide (DTBP)-promoted difunctionalization of α-aryl α-alkynyl allylic alcohols with alkyl nitriles was developed, affording a series of α-alkynyl γ-cyano functionalized ketones in moderate yields.

Mechanistic study on the regioselective Ni-catalyzed methylation-alkenylation of alkyne with AlMe3 and allylic alcohol

The recently reported Ni-catalyzed methylation-allylation of alkynes with allylic alcohols and AlMe3 reagents delivers valuable tetrasubstituted alkene unit in a highly regioselective fashion. Motivated by the experimental significance and the...