477808-38-1Relevant academic research and scientific papers
Asymmetric synthesis of β-amino cyclohexyl sulfonates, β-sultams and γ-sultones
Enders, Dieter,Wallert, Stefan,Runsink, Jan
, p. 1856 - 1868 (2007/10/03)
An efficient asymmetric synthesis of β-aminocyclohexyl sulfonates, β-sultams and γ-sultones has been developed. The key step of the synthesis is the Lewis acid catalyzed aza-Michael addition of the enantiopure hydrazines SAMP [(S)-1] or RAMBO [(R,R,R)-2] to alkenylcyclohexyl sulfonates 3. This leads to β-hydrazino sulfonates 4a-k in moderate to good yields (41-85%) and diastereomeric excesses (de = 44-90%). The epimers were separated by preparative HPLC. Subsequent reductive N-N bond cleavage with BH 3·THF and protection of the resulting amines with CbzCl gave N-Cbz-protected β-aminocyclohexyl sulfonates 6a-k in moderate to good yields (38-68% over 2 steps) and high enantiomeric excesses (ee ≥ 96%). α-Alkylation of 6 with various electrophiles afforded α-alkyl-β -aminocyclohexyl sulfonates 10a-g in good to excellent yields (67-92%) and moderate to high diastereomeric excesses (de = 71-93%). After alkylation with allyl iodide, the first asymmetric iodosultonization was achieved with high selectivities. Compounds 6g-k were also cyclized in a four-step synthesis to highly enantio-enriched 3-substituted-1,2-thiazetidine 1,1-dioxides (β-sultams) 9a-e.
Efficient asymmetric synthesis of 3-substituted β-sultams
Enders, Dieter,Wallert, Stefan
, p. 5109 - 5111 (2007/10/03)
The asymmetric synthesis of 3-substituted 1,2-thiazetidine 1,1-dioxides by cyclization of β-amino-sulfonyl chlorides is reported. The synthesis is based on the aza-Michael addition of (R,R,R)-2-amino-3-methoxymethyl-2-azabicyclo[3.3.0]octane (RAMBO) to al
