Improved Synthesis of 1‐Benzenesulfinyl Piperidine and Analogs for the Activation of Thioglycosides in Conjunction with Trifluoromethanesulfonic Anhydride*

Abstract

An improved protocol for the large scale production of 1-benzenesulfinyl piperidine and other sulfinamides is described. It is demonstrated that 1-benzenesulfinyl pyrrolidine and N,N-diethyl benzenesulfinamide function analogously to 1-benzenesulfinyl piperidine in the trifluoromethanesulfonic anhydride-mediated activation of thioglycosides, and that their less crystalline nature enables them to be used at −78 °C as opposed to the −60 °C required to keep 1-benzenesulfinyl piperidine in solution. N,N-Dicyclohexyl benzenesulfinamide does not activate thioglycosides in combination with trifluoromethanesulfonic anhydride which is attributed to its greater steric bulk.

Influence of O6 in Mannosylations Using Benzylidene Protected Donors: Stereoelectronic or Conformational Effects?

“…The product was purified twice by dry column chromatography, but it was not possible to remove unreacted BSP (ratio 1:0.8) which can be seen in the spectra. The peaks from BSP are in accordance with previous published data . Because of the multiple purifications, heptane is present in the spectra: HRMS (ESI) m / z calcd for C 40 H 48 O 10 Na + 711.3145, found 711.3153; 1 H NMR (500 MHz, CDCl 3 ) δ 7.69–7.63 (dd, J = 8.0, 1.6 Hz, 2H; Ph), 7.37–7.28 (m, 13H; Ph), 5.85–5.82 (d, J = 3.5 Hz, 1H; H-1′), 5.20–5.17 (d, J 1,2 = 1.3 Hz, 1H; H-1), 4.79–4.71 (m, 3H; 3 × CH(H)Ph), 4.61–4.58 (m, 1H; CH(H)Ph), 4.57–4.53 (m, 2H; H-2′, H-8), 4.29–4.27 (d, J = 2.0 Hz, 1H; H′), 4.10–4.07 (m, 1H; H-6 a ′), 4.05–4.03 (dd, J = 3.6, 2.3 Hz, 2H; H′, H-6 b ′), 4.03–4.00 (m, 1H; H′), 3.95–3.91 (t, J = 9.3 Hz, 1H; H-4), 3.82–3.78 (m, 2H; H-2, H-3), 3.58–3.53 (m, 1H; H-5), 2.16–2.10 (ddd, J = 16.2, 10.8, 3.3 Hz, 2H; H-6 a , H-7 a ), 1.90–1.85 (m, 1H; H-6 a ), 1.76–1.72 (m, 1H, H-7 a ), 1.50–1.49 (s, 3H; CH 3 C), 1.41–1.40 (s, 3H; CH 3 C), 1.34–1.33 (s, 3H; CH 3 C), 1.32–1.31 (s, 3H; CH 3 C).…”

Influence of the O3 Protecting Group on Stereoselectivity in the Preparation ofC-Mannopyranosides with 4,6-O-Benzylidene Protected Donors

“…With the various donors in hand, a series of C -glycoside-forming reactions, with acceptors of varying nucleophilicity, were conducted as reported in Table with activation by the BSP/TTBP/Tf 2 O cocktail or the DPSO/TTBP/Tf 2 O mixture recommended for the activation of thioglycosides by van Boom and co-workers or for the sulfoxide by Tf 2 O/TTBP …”

A New, Powerful Glycosylation Method: Activation of Thioglycosides with Dimethyl Disulfide−Triflic Anhydride

“…An attractive feature of some of these promoter systems containing sulfinyl derivatives lies in their power, glycosylation successfully being performed at low temperatures. Nevertheless, as most of these sulfinyl derivatives are not commercially available, improvement of their synthetic accessibility, as well as their stability and solubility, is desired …”