227805-01-8

Upstream product

• 227804-97-9 (3S,4R)-3-benzyl-4-({[2S-(methoxymethyl)tetrahydro-1H-1-pyrrolyl]imino}methyl)tetrahydro-2H-pyran-2-one 
• 3393-45-1 5,6-dihydro-pyran-2-one 
• 227804-94-6 (4R)-4({[(2S)-(methoxymethyl)tetrahydro-1H-1-pyrrolyl]imino}methyl)tetrahydro-2H-pyran-2-one 

Relevant academic research and scientific papers

Asymmetric synthesis of α-substituted β-formyl δ-lactones via a Michael addition/α-alkylation protocol

An efficient trans-diastereo- and enantioselective synthesis of α- substituted β-formyl δ-lactones 5 (de ≥98%, ee = 80 - 95%) is described, employing formaldehyde-SAMP-hydrazone (1) as a neutral formyl anion equivalent. The new procedure involves the Michael addition of 1 to 5,6- dihydro-2H-pyran-2-one (2) followed by trans-selective α-alkylation and subsequent oxidative cleavage of the auxiliary.

Formaldehyde SAMP-hydrazone as a neutral formyl anion equivalent: Asymmetric synthesis of substituted β-formyl δ-lactones and furofuran lactones

An efficient asymmetric synthesis of α-substituted β-formyl δ- lactones 5 (de ≥98%, ee = 80-95%) and 4-substituted furofuran lactones 6 (de ≥ 98%, ee = 80->98%) in acceptable overall yields is reported. Key steps of the new procedure are an asymmetric Michael addition of formaldehyde SAMP- hydrazone (1) to 5,6-dihydro-2H-pyran-2-one (2) under neutral conditions, followed by trans-selective α-alkylation and subsequent cleavage of the auxiliary by ozonolysis or a hydrolytic domino reaction protocol, respectively. The absolute configurations given for the title compounds are based on three X-ray structure analyses and NOE measurements.