Chemo-enzymatic synthesis of key intermediates (S)-γ-hydroxymethyl-α,β-butenolide and (S)-γ-hydroxymethyl-γ-butyrolactone via lipase-mediated Baeyer–Villiger oxidation of levoglucosenone

Abstract

Baeyer–Villiger oxidation of levoglucosenone with CAL-B and solid buffers provided valuable lactones in high yields in only 2 hours while allowing enzyme recyclability.

Chemo-Enzymatic Synthesis of Chiral Epoxides Ethyl and Methyl (S)-3-(Oxiran-2-yl)propanoates from Renewable Levoglucosenone: An Access to Enantiopure (S)-Dairy Lactone

“…Even though the m-CPBA-and zeolites-based Baeyer-Villiger oxidations lead to slightly better yields, lipase-mediated Baeyer-Villiger oxidation is preferred because it avoids not only the use of potentially explosive organic peroxide and harmful organic solvent (dichloromethane), but also the production of stoichiometric amount of by-product (i.e., m-chlorobenzoic acid). In addition, the enzyme is used in catalytic amount and can be easily recycled by simple filtration [24,25].…”

“…Synthesis of (S)-γ-Hydroxymethyl-γ-butyrolactone (2) The synthesis of the epoxides (S)-1a and (S)-1b started with the preparation of key intermediate (S)-γ-hydroxymethyl-γ-butyrolactone (2) from LGO using the two chemo-enzymatic pathways we previously developed and optimized [24,25] (Scheme 4). The first one consisted in performing a palladium-catalyzed hydrogenation of LGO (87%) followed by the Baeyer-Villiger oxidation of the resulting saturated LGO (2H-LGO, or Cyrene™) in ethyl acetate and in the presence of hydrogen peroxide and CAL-B (aka Novozyme 435 ® , N435 or immobilized lipase Candida antarctica type B); the subsequent acid hydrolysis of the reaction mixture with Amberlyst 15 IR dry in ethanol then provides 2 in 65% overall yield.…”

“…The second pathway involves the exact same reactions but in a reversed fashion (i.e., Baeyer-Villiger oxidation of LGO, acid hydrolysis and palladium-catalyzed hydrogenation) providing 2 in 70% overall yield from LGO. It is noteworthy that the above Baeyer-Villiger oxidation of LGO can be performed either chemically-using AcOOH (75%) [34,35], zeolites (96% HPLC yield) [36] or m-CPBA (85%) [34,35]-or enzymatically with a lipase (80%) [24,25]. Even though the m-CPBA-and zeolites-based Baeyer-Villiger oxidations lead to slightly better yields, lipase-mediated Baeyer-Villiger oxidation is preferred because it avoids not only the use of potentially explosive organic peroxide and harmful organic solvent (dichloromethane), but also the production of stoichiometric amount of by-product (i.e., m-chlorobenzoic acid).…”

“…Recently, we reported on the eco-friendly synthesis of 2 by a chemo-enzymatic process from levoglucosenone (LGO) [21][22][23][24][25] a valuable chiral chemical platform obtained from flash pyrolysis of cellulosic residues, such as softwood sawdust (Furacell™ process) [26]. Providing 2 in very good yield and high purity through a lipase-based mediated oxidation, this sustainable synthetic pathway has been studied further by our group as an alternative to the one involving L-glutamic acid to achieve the synthesis of epoxides (S)-1a and (S)-1b (Scheme 2).…”

Sn-based catalysts for Baeyer-Villiger oxidations by using hydrogen peroxide as oxidant

“…Since valuable lactones or esters can be obtained directly from the corresponding ketones, BV oxidation has become one of the most important transformations in organic synthesis [3][4][5][6]. Generally, percarboxylic acids (i.e., meta-chloroperbenzoic acid (m-CPBA), peracetic acid, etc.)…”