References
- Catalysis of Organic Reactions by Supported Inorganic Reagents Clark, J. H.
- Tetrahedron v.55 Sen, S. E.;Smith, S. M.;Sullivan, K. A.
- Chem. Mater v.8 Sayari, A.
- Science v.267 Tanev, P. T.;Pinnavaia, T. J.
- Chem. Mater. v.8 Tanev, P. T.;Pinnavaia, T. J.
- Synlett Mode, J. E. G.;Clark, J. H.;Macquarrie, D. J.
- Synlett Itoh, a.;Masaki, Y.
- Protective Groups in Organic Synthesis Green, T. W.;Wuts, P. G. M.
- Protecting Groups Kocienski, P. J.
- Angew. Chem. Int. Ed. Engl. v.35 Schelhaas, M.;Waldmann, H.
-
HMS used in this experiment was prepared according to the literature
$method^5$ using dodecyl amine as template and tetraethyl orthosilicate (TEOS) as silicon source. Template removal was achieved by ethanol extraction. Thus, neat TEOS (44.6 mL, 0.20 mol) was added to a well-stirred solution of dodecyl amine (10.0 g, 0.054 mol) in EtOH (105.5 mL) and H₂O (106.7 mL) all at once at rt. The whole mixture was stirred for 18 h at rt and the solid product was filtered, washed with deionized water (800 mL), and air-dried for 1 day. The pale yellow solid (21.4 g) was extracted with EtOH (500 mL) in a Soxhlet extractor for 4 h. The solvent-extracted material was dried at 80 ℃ for 3 h and calcined in air at 630 ℃ for 4 h (heating rate 2 ℃/min) to give 9.60 g of white solid. The physicochemical parameters of HMS prepared thus are as follows: BET surface area 1142 ± 19 ㎡/g, average pore diameter 41 Å, micropore volume 0.67 mL/g - The less reactivity observed in entry 3 is probably due to the electronic effect
- Generally, dimethyl acetals are less reactive than ketals in the acid-catalysed cleavage. See Ref. 8a
- Tetrahedron Lett. v.16 Ellison, R. A.;Lukenbach, E. R.;Chiu, C.-W.
- When a solution of demethyl acetal of benzaldehyde in dry chloroform and water was refluxed for 24 h in the absence of HMS, deprotection did not occur
- Synthetic Commun. v.22 Rao, M. N.;Kumar, P.;Singh, A. P.;Reddy, R. S.