Page 5 of 7
New Journal of Chemistry
Please do not adjust margins
Journal Name
rearranged to aldehyde [E] and release HMnO3. Further
COMMUNICATION
1
2
3
4
5
6
7
8
Notes and references
1
(a) T. W. Greene and P. G. M. WutsD, OPIr:o1t0e.1c0t3iv9e/DG0NroJ0u4p3s21iDn
Organic Synthesis, Wiley, New York, 4th edn, 2006; (b) P. J.
Kocienski, Protecting Groups, Thieme, New York, 1994.
(a) K.-T. Huang, B.-C. Wu, C.-C. Lin, S.-C. Luo, C. Chen, C.-H.
Wong and C.-C. Lin, Carbohydr. Res., 2006, 341, 2151-2155;
(b) J. B. Schwarz, S. D. Kuduk, X.-T. Chen, D. Sames, P. W.
Glunz and S. J. Danishefsky, J. Am. Chem. Soc., 1999, 121,
2662-2673.
(a) J. Žemlička, J. Beránek and J. Smrt, Collect. Czech. Chem.
Commun., 1962, 27, 2784-2795; (b) C. B. Reese and J. C. M.
Stewart, Tetrahedron Lett., 1968, 9, 4273-4276; (c) V.
Schwarz, Czech. Chem. Commun., 1962, 27, 2567-2574; (d) T.
B. Winholdz, D. B. R. Johnston, Tetrahedron Lett., 1967, 8,
2555-2557.
oxidation could be eliminated by diminishing the acidic
conditions thus preventing the conversion of Mn(V) i.e.
,
HMnO3 into higher-valent Mn(VII),23 the later favors oxidation
2
of aldehyde to acid.
In summary, we have established
a
mild and
chemoselective deprotection of acetyl ester employing a
catalytic amount of KMnO4 in open atmosphere at ambient
temperature. The operationally convenient method tolerates
electronically diverse functionalities and orthogonal with
several sensitive protecting groups. The protocol is broadly
applicable and successfully applied for a wide range of
substrates enabling rapid and chemoselective deacetylation.
The intrinsic dual-reactivity of KMnO4 leading to selective
deacetylation and controlled-oxidation in one-pot process is
amply useful. The improved protocol utilizing the
environmentally benign chemicals is highly advantageous over
conventional method ensuring the clean and quantitative
transformation of benzyl acetates into corresponding
aldehydes. We believe that these results will likely to
contribute significantly in synthetic organic chemistry and find
its utility as an alternative reagent system.
SK gratefully acknowledges the Department of Science and
Technology, India for the Early Career Research Award and
Research Grant for Young Scientists (SERB-ECR/2017/001477).
The author thanks TEQIP-III for generous support and MRC
MNIT (Advanced Analytical and Characterization Centre) for
providing NMR spectroscopic and analytical data. The authors
are also grateful to the Director MNIT for providing necessary
infrastructure. AG acknowledges a UGC Fellowship.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
3
4
(a) V. Pozsgay, J. Am. Chem. Soc., 1995, 117, 6673-6681; (b)
N. Yamamoto, T. Nishikawa and M. Isobe, Synlett, 1995, 505-
506; (c) E. J. Corey, D. A. Clark, G. Goto, A. Marfat, C.
Mioskowski, B. Samuelsson and C. Hammarström, J. Am.
Chem. Soc., 1980, 102 , 1436-1439; (d) N. E. Byramova, M. V.
Ovchinnikov, L. Backinowsky and N. K.
Kochetkov,
Carbohydr. Res., 1983, 124, C8-C11.
5
6
L. H. B. Baptistella, J. F. dos Santos, K. C. Ballabio and A. J.
Marsaioli, Synthesis, 1989, 436-439.
(a) N. Kunesch, C. Meit and J. Poisson, Tetrahedron Lett.,
1987, 28, 3569-3572; (b) U. Ellervik and G. Magnusson,
Tetrahedron Lett., 1997, 38, 1627-1628.
V. Pozsgay and B. Coxon, Carbohydr. Res., 1993, 257, 189-
215.
R. Yanada, N. Negoro, K. Bessho and K. Yanada, Synlett,
1995, 1261-1263.
T. Neilson and E. S. Werstiuk, Can. J. Chem., 1971, 49, 493-
499.
7
8
9
10 Y. Ishido, N. Nakazaki and N. Sakairi, J. Chem. Soc., Perkin
Trans. 1, 1979, 2088-2098.
11 M. G. Perez and M. S. Maier, Tetrahedron Lett. 1995, 36,
3311-3314.
Experimental
Representative procedure for the chemoselective deacetylation
and one-pot deacetylation-oxidation;
12 (a) Y.-C. Xu, A. Bizuneh and C. Walker, J. Org. Chem., 1996,
61, 9086-9089; (b) Y.-C. Xu, E. Lebeau and C. Walker,
Tetrahedron Lett., 1994, 35, 6207-6210; (c) Y.-C. Xu, A.
Bizuneh and C. Walker, Tetrahedron Lett., 1996, 37, 455-458.
13 A. G. González, I. Brouard, F. León, J. I. Padrón and B. Jaime,
Tetrahedron Lett., 2001, 42, 3187-3188.
14 (a) K. Naemura, N. Takahashi and H. Chikamatsu, Chem.
Lett., 1988, 30, 1717-1720; (b) C. R. Johnson and C. H.
Senanayake, J. Org. Chem., 1989, 54, 735-736; (c) O. Houille,
T. Schmittberger and D. Uguen, Tetrahedron Lett., 1996, 37,
625-628; (d) R. López, E. Montero, F. Sánchez, J. Cañada and
A. Fernández-Mayoralas, J. Org. Chem., 1994, 59, 7027-7032;
(e) E. W. Holla, V. Sinnwell and W. Klaffke, Synlett, 1992,
413-414; (f) T. Itoh, A. Uzu, N. Kanda and Y. Takagi,
Tetrahedron Lett., 1996, 37, 91-92; (g) K. Takabe, N. Mase, T.
Hisano and H. Yoda, Tetrahedron Lett., 2003, 44, 3267-3269;
(h) T. Hisano, K. Onodera, Y. Toyabe, N. Mase, H. Yoda and K.
Takabe, Tetrahedron Lett., 2005, 46, 6293-6295.
15 (a) D. S. Rao, T. R. Reddy, A. Gurawa, M. Kumar and S.
Kashyap, Org. Lett., 2019, 21, 9990-9994; (b) T. R. Reddy, D.
S. Rao and S. Kashyap, Chem. Commun., 2019, 55, 2833-
2836; (c) D. S. Rao, T. R. Reddy and S. Kashyap, Org. Biomol.
Chem., 2018, 16, 1508-1518; (d) D. S. Rao, T. R. Reddy, K.
Babachary and S. Kashyap, Org. Biomol. Chem., 2016, 14,
7529-7543; (e) T. R. Reddy, D. S. Rao, K. Babachary and S.
Kashyap, Eur. J. Org. Chem., 2016, 291-311; (f) G. Kundoor,
D. S. Rao and S. Kashyap, Asian J. Org. Chem., 2016, 5, 264-
270; (g) S. Chittela, T. R. Reddy, P. R. Krishna and S. Kashyap,
J. Org. Chem. 2015, 80, 7108-7116; (h) T. R. Reddy, D. S. Rao
and S. Kashyap, RSC Adv., 2015, 5, 28338-28343; (i) S.
A preformed solution of benzyl acatate 1 (50 mg, 1.0 equiv.)
was treated with KMnO4 (0.1 equiv. for deacetylation in MeOH
(1 mL) or 1.0 equiv. for deacetylation-oxidation in
MeOH:EtOAc (9:1; 2 mL)). The mixture was stirred at room
temperature in open air environment and the reaction
progress was monitored by TLC. After the complete
consumption of starting material was observed, typically 1-12
h for deacetylation and 10-32 h for deacetylation-oxidation,
the reaction mixture was filtered and washed with EtOAc (10
mL). The resultant filtrate was treated with saturated aqueous
NaHCO3 (5 mL), and aqueous layer was extracted with EtOAc
(3 × 30 mL). The combined organic layers were washed with
water and brine, dried over anhydrous Na2SO4, and
concentrated in vacuo to obtain the analytical pure hydroxyl
products 3-11 and 13-28 or aldehydes products 29-41. For 2-
acetamidobenzyl acetate, the crude residues were purified by
silica gel column chromatography using EtOAC/Hexane to
obtain the desired 2-acetamido benzyl alcohol (12) or 2-
acetamidobenzaldehyde (42) following deacetylation-
oxidation in one-pot.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 5
Please do not adjust margins