Selective oxidation of benzylic alcohols by laccase from white-rot mushroom Tricholoma giganteum AGHP: Total synthesis of taccabulin A, taccabulin D and taccabulin E

Copper-Catalyzed Direct Thiolation of Ketones Using Sulfonohydrazides: A Synthetic Route to Benzylic Thioethers

“…22 Similarly, the reaction between hydrazone and benzene sulfonic acid failed to furnish the desired product. The results presented above and literature reports 22,24,26 led to a plausible mechanism for the regioselective thiolation of benzophenone with benzenesulfonohydrazide, as described in Scheme 7. Sulfonohydrazide (2a) and benzophenone (1a) may fi r s t r e a c t t o f o r m N ′ -( d i p h e n y l m e t h y l e n e )benzenesulfonohydrazide (I), which may then allow benzenesulfinate (III) to be released from I and produce (diazomethylene)dibenzene (II).…”

“…Therefore, in situ hydrazone synthesis will be desired. In situ hydrazone synthesis has already been explored by Barluenga et al 24 By carefully reviewing the reports on the synthesis of benzylic thioethers and in situ tosyl hydrazine synthesis along with our previous work, 25 we came to the conclusion that benzylic thioethers might be produced from ketones by forming sulfonyl hydrazones in situ and then benzyl thioethers. Also, as an outcome, we herein report an applied protocol for the direct synthesis of benzylic thioethers via in situ formation of sulfonyl hydrazone (Scheme 2).…”

Laccases from Pleurotus ostreatus Applied to the Oxidation of Furfuryl Alcohol for the Synthesis of Key Compounds for Polymer Industry

“…Unfortunately, high enzyme loadings, low conversions or high quantities of the mediator had to be employed, respectively. Furthermore, Waghmode and co‐workers reported the oxidation of several alcohols, including furfuryl alcohol, employing TEMPO in combination with Tricholoma giganteum laccase [26] . However, 75 mol % of TEMPO and 1,500 U mL −1 of enzyme at 37 °C had to be used to obtain quantitative furfural accumulation.…”

“…Furthermore, Waghmode and co-workers reported the oxidation of several alcohols, including furfuryl alcohol, employing TEMPO in combination with Tricholoma giganteum laccase. [26] However, 75 mol % of TEMPO and 1,500 U mL À 1 of enzyme at 37 °C had to be used to obtain quantitative furfural accumulation. These facts prompted us to study other laccases, such as the ones from P. ostreatus, to accomplish this transformation.…”

Organocatalytic Approach to the Enantioselective Total Synthesis of (+)-Serinolamides A and B and (+)-Lacosamide

“…As part of our research program on the development of new strategies for the total synthesis 18a and enantioselective syntheses of biologically active compounds and their key chiral intermediates based on proline-catalyzed asymmetric α-amination of aldehydes, 18b c we have established a new promising route for the synthesis of (+)-serinolamide A ( 2 ), (+)-serinolamide B ( 3 ), and (+)-lacosamide ( 7 ) from the intermediate di- tert -butyl ( R / S )-1-(1-hydroxy-3-methoxypropan-2-yl)hydrazine-1,2-dicarboxylate ( 9 / 9a ) obtained from l -proline-catalyzed α-amination of 3-methoxypropanal ( 8 ). Other crucial steps in these syntheses include Grubbs’ metathesis and acid-amine coupling reactions.…”