Copper-Catalyzed Asymmetric Sulfonylative Desymmetrization of Glycerol

Glycerol is the main side product in the biodiesel manufacturing process, and the development of glycerol valorization methods would indirectly contribute the sustainable biodiesel production and decarbonization. Transformation of glycerol to optically active C3 units would be one of the attractive routes for glycerol valorization. We herein present the asymmetric sulfonylative desymmetrization of glycerol by using a CuCN/(R,R)-PhBOX catalyst system to provide an optically active monosulfonylated glycerol in high efficiency. A high degree of enantioselectivity was achieved with a commercially available chiral ligand and an inexpensive carbonate base. The optically active monosulfonylated glycerol was successfully transformed into a C3 unit attached with differentially protected three hydroxy moieties. In addition, the synthetic utility of the present reaction was also demonstrated by the transformation of the monosulfonylated glycerol into an optically active synthetic ceramide, sphingolipid E.

An enantiodivergent synthesis of N-Boc-protected (R)- and (S)-4-amino cyclopent-2-en-1-one

Routes are reported for the synthesis of both (1 R)- and (1 S)- tert-butyl-(4-oxocyclopent-2-en-1-yl)carbamate 2. Featuring Mitsunobu reactions with di- tert-butyl iminodicarbonate, both syntheses begin from ( S)-4-[( tert-butyldimethylsilyl)oxy]cyclopent-2-en-1-one (3) and take advantage of the 1,4-cyclopentenyl dioxygenation pattern of this optically active starting material. Thus both (−)- and (+)-2 have been accessed from 3 in an enantiodivergent manner in 11% and 10% overall yield over five and seven reaction steps, respectively.