ChemInform Abstract: Stereoselectivity of the Honda—Reformatsky Reaction in Reactions with Ethyl Bromodifluoroacetate with α‐Oxygenated Sulfinylimines.

Abstract

Stereoselectivity of the Honda-Reformatsky Reaction in Reactions with EthylBromodifluoroacetate with -Oxygenated Sulfinylimines. -The Honda--Reformatsky reaction involving bromodifluoroacetate (II) is investigated with both sulfinylimines derived from aliphatic aldehydes as well as those derived from aldehydes bearing a chiral -oxygenated substituent. The Reformatsky reaction of the latter proceeds with double diastereodifferentiation, with the configuration of the chiral sulfoxide determining the stereoinduction. On the contrary, sulfinylimines derived from unsubstituted alkanals react with virtually no diastereoselectivity. -(FONTENELLE, C. Q.; CONROY, M.; LIGHT, M.; POISSON, T.; PANNECOUCKE, X.; LINCLAU*, B.; J. Org. Chem. 79 (2014) 9, 4186-4195, http://dx.doi.org/10.1021/jo500396p ; Dep. Chem., Univ. Southampton, Southampton SO17 1BJ, UK; Eng.) -H. Haber 39-033

3,4-Dideoxy-3,3,4,4-tetrafluoro- and 4-OH epimeric 3-deoxy-3,3-difluoro-α-GalCer analogues: Synthesis and biological evaluation on human iNKT cells stimulation

“…14 was observed in major amount, its isolation in pure form proved not possible. Nevertheless, Honda-Reformatsky reaction was attempted using the crude mixture with sulfinimine 16 [147] in the presence of RhCl(PPh3)3 and Et2Zn. Following this route, the sulfinamine 17 was 14 obtained in only 27% yield in an 82:18 3S/3R diastereomeric ratio, with the homocoupling 15 product 18 being obtained as the major product (36%).…”

“…)-17 and 17-(bromodifluoromethyl)-16,16-difluoro-17-hydroxyhentriacontan-15-one 18. To a solution 33of sulfinylimine (RS,E)-16[147] (105 mg, 0.414 mmol) and RhCl(PPh3)3 (12 mg, 13 µmol) in THF (2.8 mL), at -20 °C, was added a solution of ketone (176 mg, 0.495 mmol) in THF (0.5 mL) immediately followed by addition dropwise of Et2Zn (1.0 M in hexane, 0.88 mL, 0.88 mmol). The mixture was warmed to 0 °C over 1 h, and then stirred for 1 h before being quenched with aq.…”