Triphenylphosphine → N-carbobenzyloxy-4-(cis)-(4-cyanophenoxy)-L-proline methyl ester

Participants

Role	Name	HCID	Charge
Reactant	Triphenylphosphine	HCID 11776	—
Reactant	4-Cyanophenol	HCID 13019	—
Reactant	2-Methyl 1-(phenylmethyl) (2S,4R)-4-hydroxy-1,2-pyrrolidinedicarboxylate	HCID 688411	—
Reactant	Diethyl azodicarboxylate	HCID 5462977	—
Solvent	Tetrahydrofuran	HCID 8028	—
Product	N-carbobenzyloxy-4-(cis)-(4-cyanophenoxy)-L-proline methyl ester	HCID 18654599	89%

Reaction Conditions

Temperature	0 °C

Reaction Steps

To a solution of N-carbobenzyloxy-trans-4-hydroxy-L-proline methyl ester (10.0 g, 35.8 mmol) in 200 mL of anhydrous THF under N2 was added triphenylphosphine (10.6 g, 39.4 mmol) and 4-cyanophenol (4.7 g, 39.4 mmol). This solution was cooled to 0° C. and then treated with diethylazodicarboxylate (6.3 mL, 39.4 mmol), added dropwise over 30 minutes. The reaction was warmed to room temperature and stirred for 2 days. The solvent was removed in vacuo, and the residue chromatographed (SiO2, 30% ethyl acetate/hexanes) to provide 12.1 g (89%) of N-carbobenzyloxy-4-(cis)-(4-cyanophenoxy)-L-proline methyl ester as a colorless oil. (MS).

Provenance & Evidence

DOI	10.6084/m9.figshare.5104873.v1
Patent number	US05344937
Source dataset	uspto-grants-1994_09
ORD ID	ord-f50a3591c3794cf193d2eeddd73def75
Source note	uspto-grants-1994_09