01783nas a2200157   4500008004100000245014300041210006900184260000800253300001600261490000700277520113400284100002401418700002601442700002801468856012901496       2022                        eng d00aGlycal mediated synthesis of piperidine alkaloids: fagomine, 4-epi-fagomine, 2-deoxynojirimycin, and an advanced intermediate, iminoglycal0 aGlycal mediated synthesis of piperidine alkaloids fagomine 4epif  cNOV  a33021-330310 v123 a<p>
	Glucal and galactal are transformed into 2-deoxyglycolactams, which are important building blocks in the synthesis of biologically active piperidine alkaloids, fagomine and 4-epi-fagomine. In one of the strategies, reduction of 2-deoxyglycolactam-N-Boc carbonyl by lithium triethylborohydride (Super-Hydride (R)) has been exploited to generate lactamol whereas reduction followed by dehydration was utilized as the other strategy to functionalize the C-1-C-2 bond in the iminosugar substrate. The strategies provide the formal synthesis of 2-deoxynojirimycin, nojirimycin and nojirimycin B. DFT studies were carried out to determine the reason for the failure of the formation of the 2-deoxygalactonojirimycin derivative. Further, DFT studies suggest that phenyl moieties of protecting groups and lone pairs of oxygen in carbamate group plays a vital role in deciphering the conformational space of the reaction intermediates and transition-state structures through cation-pi or cation-lone pair interactions. The influence of these interactions is more pronounced at low temperature when the entropy factor is small.</p>
1 aChand, Hemender, R.1 aTiwari, Mritunjay, K.1 aBhattacharya, Asish, K.  uhttps://library.ncl.res.in/content/glycal-mediated-synthesis-piperidine-alkaloids-fagomine-4-epi-fagomine-2-deoxynojirimycin