Monday, 15 August 2016

Combination of Enabling Technologies to Improve and Describe the Stereoselectivity of Wolff–Staudinger Cascade Reaction

SYNTHESIS Highlight

Image by Steven V. Ley and co-workers

Augmented Reality: New perspectives for the visualization of molecules
This SYNTHESIS paper highlights the combination of enabling technologies to improve the stereoselectivity of a Wolff–Staudinger cascade reaction.

Read Article

›

Synthesis
DOI: 10.1055/s-0035-1562579

paper

Combination of Enabling Technologies to Improve and Describe the Stereoselectivity of Wolff–Staudinger Cascade Reaction

B. Musioa, F. Mariania, b, E. P. Śliwińskia, M. A. Kabeshova, H. Odajimac, S. V. Ley*a

aUniversity of Cambridge, Department of Chemistry, Lensfield Road, Cambridge, CB2 1EW, UK Email:svl1000@cam.ac.uk
bUniversitat de Barcelona, Laboratori de Química Orgànica, Facultat de Farmàcia, Av. Joan XXIII s/n, 08028 Barcelona, Spain
cSaida FDS, 143-10 Itsushiki, Yaizu-shi, Shizuoka Prefecture 4250054, Japan

https://www.thieme-connect.de/products/ejournals/html/10.1055/s-0035-1562579?update=true

Abstract

A new, single-mode bench-top resonator was evaluated for the microwave-assisted flow generation of primary ketenes by thermal decomposition of α-diazoketones at high temperature. A number of amides and β-lactams were obtained by ketene generation in situ and reaction with amines and imines, respectively, in good to excellent yields. The preferential formation of trans-configured β-lactams was observed during the [2+2] Staudinger cycloaddition of a range of ketenes with different imines under controlled reaction conditions. Some insights into the mechanism of this reaction at high temperature are reported, and a new web-based molecular viewer, which takes advantage from Augmented Reality (AR) technology, is also described for a faster interpretation of computed data.

N-Benzyl-2-[4-(trifluoromethyl)phenyl]acetamide (4a)

Yield: 65%; white solid; mp 134–136 °C.

1H NMR (600 MHz, CDCl3): δ = 7.61 (d, J = 8.05 Hz, 2 H), 7.41 (d, J = 8.00 Hz, 2 H), 7.32 (d, J = 7.53 Hz, 2 H), 7.28–7.34 (m overlapping d at 7.32 ppm, 1 H), 7.22 (d, J = 7.13 Hz, 2 H), 5.89 (br. s, 1 H), 4.43 (d, J = 5.8 Hz, 2 H), 3.64 (s, 2 H).

13C NMR (150.0 MHz, CDCl3): δ = 169.7, 138.8 (br s), 137.8, 129.6, 129.59 (q, J C–F = 32.5 Hz), 128.7, 127.62, 127.59, 125.8 (q, J C–F = 3.8 Hz), 124.0 (q, J C–F = 272.0 Hz), 43.8, 43.3.

IR (neat): 3238, 3063, 1625, 1556, 1328, 1122, 1070, 753, 698 cm–1.

HRMS: m/z [M + H]+ calcd for C15H15F3NO: 294.1100; found: 294.1090.