Formaldehyde → (R)-(9H-fluoren-9-yl)methyl 4-((tert-butyldisulfanyl)methyl)-5-oxooxazolidine-3-carboxylate

Participants

Role	Name	HCID	Charge
Reactant	Formaldehyde	HCID 712	—
Reactant	3-((1,1-dimethylethyl)dithio)-N-((9H-fluoren-9-ylmethoxy)carbonyl)-L-alanine	HCID 16213190	—
Catalyst	Bicyclo[2.2.1]heptane-1-methanesulfonic acid, 7,7-dimethyl-2-oxo-, (1S)-	HCID 18462	—
Solvent	Toluene	HCID 1140	—
Product	(R)-(9H-fluoren-9-yl)methyl 4-((tert-butyldisulfanyl)methyl)-5-oxooxazolidine-3-carboxylate	HCID 89396784	94.3%

Reaction Conditions

Temperature	100 °C

Reaction Steps

Paraformaldehyde (843 mg, 9.26 mmol) and 10-camphorsulfonic acid (75 mg, 0.324 mmol) were added to a solution of (R)-2-((((9H-fluoren-9-yl)methoxy)carbonyl)amino)-3-(tert-butyldisulfanyl)propanoic acid (Compound 2α-B) (2.00 g, 4.63 mmol) in toluene (10 ml), and the mixture was stirred at 100° C. for 4 hours. The reaction mixture was returned to room temperature and then concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (hexane/ethyl acetate=100/0→70/30) to afford (R)-(9H-fluoren-9-yl)methyl 4-((tert-butyldisulfanyl)methyl)-5-oxooxazolidine-3-carboxylate (Compound 2b-B) (1.936 g, 94%).

Provenance & Evidence

DOI	10.6084/m9.figshare.5104873.v1
Patent number	US09409952B2
Source dataset	uspto-grants-2016_08
ORD ID	ord-68a515585bfc4bef986921755b9c021f
Source note	uspto-grants-2016_08