313699-11-5

Upstream product

• 109-80-8 1.3-propanedithiol 
• 285988-20-7 (3S,4E,2'R)-N-{3(S)-(benzo[1,3]dioxol-5-yl)-4-[2'-(methoxymethyl)pyrrolidin-1'-ylimino]-butyl}-4-methylbenzenesulfonamide 
• 285988-16-1 (R)-E-(2-benzo[1,3]dioxol-5-yl-ethylidene)-(2-methoxymethyl-pyrrolidine-1-yl)-amine 
• 6543-34-6 benzo[1,3]dioxol-5-yl-acetaldehyde 
• 3634-89-7 N-(p-toluenesulfonyl)aziridine 

Relevant academic research and scientific papers

Asymmetric total synthesis of the 1-epi-aglycon of the cripowellins A and B

The unusual [5.3.2]-bicyclic structure of the insecticidal Amaryllidaceae alkaloids cripowellin A (1) and B (2) has been synthesized for the first time via a sequence of Sharpless dihydroxylation, ring-closing metathesis, and intramolecular Heck reaction. The asymmetric synthesis of the 1-epi-aglycon 82 proceeds with virtually complete diastereo- and enantioselectivity (de, ee ≥ 98%) in 13 steps and an overall yield of 5.6%. In addition, three alternative approaches toward the aglycon 3 are also described focusing on (1) the alkylation of the 2-benzazepinedithianes 35 and 36 with the electrophile 11, (2) a radical cyclization of the precursor (R/S,S,S)-39, and (3) an intramolecular arylation reaction of the aryl ketone 47.

Asymmetric β-aminoethylation of ketones and nitriles with tosylaziridines employing the SAMP-hydrazone method

The nucleophilic ring-opening of tosylaziridines with chiral aza-enolates is reported. The SAMP-/ RAMP-hydrazones 1a-h derived from aldehydes or ketones were reacted with tosylaziridine 2a to give the β-aminoethylated hydrazones 3a-h with good diastereoselectivity. Removal of the chiral auxiliary resulted in the formation of the γ-amino nitriles 4a-e or γ-amino ketones 6f-h in good yields and excellent enantiomeric excesses (ee ≥ 98%). Ring-opening of the enantiopure, benzyl-substituted tosylaziridine 2b with aza-enolates was achieved selectively at the less-substituted ring-carbon atom, again with excellent diastereoselectivity. Subsequent cleavage of the chiral auxiliary yielded the γ-benzyl-substituted γ-amino nitrile 4j or γ-amino ketone 6i with de,ee ≥ 98%, respectively. The relative and absolute configuration of the new stereogenic centre of the aminoethylated hydrazones 3a-j was determined by NOE measurements and confirmed by X-ray structure analysis on the Mosher amide of 6h.