A new direct synthesis of α-methylene- and α-alkylidene-β-lactams

Abstract

International audienceThe Kinugasa reaction applied to alkynes bearing a nucleofuge in propargylic position affords directly, and in fair yields, α-methylene- or α-alkylidene- β-lactam

A General Convergent Strategy for the Synthesis of Tetra‐Substituted Furan Fatty Acids (FuFAs)

“…High resolution mass spectra were carried out on a Thermofisher exactive (orbi) resolution mass spectrometer. (±)‐Oct‐1‐yn‐3‐ol,[19a] (±)‐tridec‐12‐en‐1‐yn‐3‐ol,[19b] (±)‐tetradic‐1‐yn‐3‐ol[19c] and (±)‐12‐(( tert ‐butyldiphenylsilyl)oxy)dodecanal[19d] and methyl 3‐oxooctanoate ( 31 ) were prepared using literature methods.…”

“…(±)‐Methyl tridec‐12‐en‐1‐yn‐3‐yl carbonate (33) . Using the general procedure with (±)‐tridec‐12‐en‐1‐yn‐3‐ol[19b] (0.676 g, 3.50 mmol) and methyl chloroformate, the title compound 33 was isolated by column chromatography (19:1, light petroleum/ethyl acetate) as a pale‐yellow liquid (0.634 g, 2.76 mmol, 79 %). 1 H NMR (400 MHz, CDCl 3 ) δ = 5.83 (1H, ddt, J = 17.6, 8.0 and 6.8 Hz), 5.21 (1H, td, J = 6.4 and 2.0 Hz), 5.04–4.93 (2H, m), 3.83 (3H, s), 2.53 (1H, s), 2.08–2.03 (2H, m), 1.89–1.77 (2H, m), 1.48–1.41 (2H, m), 1.41–1.24 (10H, m) ppm; 13 C NMR (100 MHz, CDCl 3 ) δ = 155.0, 139.2, 114.1, 80.1, 74.9, 67.9, 54.9, 34.5, 33.8, 29.3, 29.07, 29.03, 28.9, 24.7 ppm; IR (neat) 3295, 3077, 2927, 2855, 1753, 1640, 1442, 1265, 910 cm –1 ; HRMS (ESI‐pos) m/z [M + Na + ] calcd.…”

“…(±)‐14‐(( tert ‐Butyldiphenylsilyl)oxy)tetradec‐1‐yn‐3‐yl methyl carbonate (28) . Ethynylmagnesium bromide (3.6 mL, 1.8 mmol, 0.5 m in THF) was added to a solution of 12‐(( tert ‐butyldiphenylsilyl)oxy)dodecanal[19d] (0.610 g, 1.39 mmol) in THF (3 mL) at 0 °C. The reaction was warmed to room temperature and stirred for 3 h. After addition of saturated aq.…”

From Alkynes to Heterocycles through Metal-Promoted Silylformylation and Silylcarbocyclization Reactions

“…In particular, the α-methylene-β-lactam unit is a very common structural feature included in potent β-lactamase inhibitors [98], such as asparenomycins [99,100] and penicillanic acids [101,102]. Therefore, the synthesis of α-methylene-β-lactams (3-methylene-2-azetidinones) has received great attention in the literature [103][104][105][106].…”

“…[101,102]. Therefore, the synthesis of -methylene--lactams (3-methylene-2-azetidinones) has received great attention in the literature [103][104][105][106].…”