References
<A NAME="RZ12603SS-1A">1a</A>
Greene TW.
Wuts PGM.
Protective Groups in Organic Synthesis
3rd ed.:
Wiley;
New York:
1999.
<A NAME="RZ12603SS-1B">1b</A>
Hanson JR.
Protective Groups in Organic Synthesis
Blackwell Science Inc;
Malden MA:
1999.
<A NAME="RZ12603SS-2A">2a</A>
Chakraborti AK.
Nayak MK.
Sharma L.
J. Org. Chem.
2002,
67:
1776
<A NAME="RZ12603SS-2B">2b</A>
Chakraborti AK.
Nayak MK.
Sharma L.
J. Org. Chem.
2002,
67:
2541
<A NAME="RZ12603SS-2C">2c</A>
Chakraborti AK.
Sharma L.
Sharma U.
Tetrahedron
2001,
57:
9343
<A NAME="RZ12603SS-2D">2d</A>
Chakraborti AK.
Nayak MK.
Sharma L.
J. Org. Chem.
1999,
64:
8027
<A NAME="RZ12603SS-3">3</A>
Steglich W.
Höfle G.
Angew. Chem., Int. Ed. Engl.
1969,
8:
981
<A NAME="RZ12603SS-4A">4a</A>
Iqbal J.
Srivastava RR.
J. Org. Chem.
1992,
57:
2001
<A NAME="RZ12603SS-4B">4b</A>
Ahmad S.
Iqbal J.
Tetrahedron Lett.
1986,
27:
3791
<A NAME="RZ12603SS-5">5</A>
Vedejs E.
Diver ST.
J. Am. Chem. Soc.
1993,
115:
3358
<A NAME="RZ12603SS-6A">6a</A>
Ishihara K.
Kubota M.
Kurihara H.
Yamamoto H.
J. Am. Chem. Soc.
1995,
117:
4413
<A NAME="RZ12603SS-6B">6b</A>
Ishihara K.
Kubota M.
Kurihara H.
Yamamoto H.
J. Org. Chem.
1996,
61:
4560
<A NAME="RZ12603SS-7">7</A>
Ishihara K.
Kubota M.
Yamamoto H.
Synlett
1996,
265
<A NAME="RZ12603SS-8A">8a</A>
Procopiou PA.
Baugh SPD.
Flack SS.
Inglis GGA.
J. Org. Chem.
1998,
63:
2342
<A NAME="RZ12603SS-8B">8b</A>
Procopiou PA.
Baugh SPD.
Flack SS.
Inglis GGA.
Chem. Commun.
1996,
2625
<A NAME="RZ12603SS-9">9</A>
Chauhan KK.
Frost CG.
Love I.
Waite D.
Synlett
1999,
1743
<A NAME="RZ12603SS-10A">10a</A>
Orita A.
Tanahashi C.
Kakuda A.
Otera J.
Angew. Chem., Int. Ed.
2000,
39:
2877
<A NAME="RZ12603SS-10B">10b</A>
Orita A.
Tanahashi C.
Kakuda A.
Otera J.
J. Org. Chem.
2001,
66:
8926
<A NAME="RZ12603SS-10C">10c</A>
Carrigan MD.
Freiberg DA.
Smith RC.
Zerth HM.
Mohan RS.
Synthesis
2001,
2091
<A NAME="RZ12603SS-10D">10d</A>
Mohammadpoor-Baltork I.
Aliyan H.
Khosropour AR.
Tetrahedron
2001,
57:
5851
<A NAME="RZ12603SS-11A">11a</A>
Saravanan P.
Singh VK.
Tetrahedron Lett.
1999,
40:
2611
<A NAME="RZ12603SS-11B">11b</A>
Chandra KL.
Saravanan P.
Singh RK.
Singh VK.
Tetrahedron
2002,
58:
1369
<A NAME="RZ12603SS-12">12</A>
Chandrasekhar S.
Ramachander T.
Takhi M.
Tetrahedron Lett.
1998,
39:
3263
<A NAME="RZ12603SS-13">13</A>
Ballini R.
Bosica G.
Carloni S.
Ciaralli L.
Maggi R.
Sartori G.
Tetrahedron Lett.
1998,
39:
6049
<A NAME="RZ12603SS-14A">14a</A>
Bhaskar PM.
Loganathan D.
Tetrahedron Lett.
1998,
39:
2215
<A NAME="RZ12603SS-14B">14b</A>
Li A.-X.
Li T.-S.
Ding T.-H.
Chem. Commun.
1997,
1389
<A NAME="RZ12603SS-15">15</A>
Kumareswaran R.
Pachamuthu K.
Vankar YD.
Synlett
2000,
1652
<A NAME="RZ12603SS-16">16</A>
Kumar P.
Pandey RK.
Bodas MS.
Dongare MK.
Synlett
2001,
206
<A NAME="RZ12603SS-17">17</A>
Nakae Y.
Kusaki I.
Sato T.
Synlett
2001,
1584
<A NAME="RZ12603SS-18">18</A>
Bartoli G.
Bosco M.
Dalpozzo R.
Marcantoni E.
Massaccesi M.
Rinaldi S.
Sambri L.
Synlett
2003,
39
<A NAME="RZ12603SS-19">19</A>
Dalpozzo R.
De Nino A.
Maiuolo L.
Procopio A.
Nardi M.
Bartoli G.
Romeo R.
Tetrahedron Lett.
2003,
59:
5621
<A NAME="RZ12603SS-20A">20a</A>
Forsyth SA.
MacFarlane DR.
Thomson RJ.
von Itzstein M.
Chem. Commun.
2002,
714
<A NAME="RZ12603SS-20B">20b</A>
Lee S.-G.
Park JH.
J. Mol. Catal. A: Chem.
2003,
194:
49
<A NAME="RZ12603SS-21">21</A>
Karimi B.
Maleki J.
J. Org. Chem.
2003,
68:
4951
<A NAME="RZ12603SS-22">22</A>
Chakraborti AK.
Gulhane R.
Tetrahedron Lett.
2003,
44:
6749
<A NAME="RZ12603SS-23A">23a</A>
Sweet DV.
Registry of Toxic Effects of Chemical Substances 1985-86
U. S. Govt. Printing Office;
Washington D.C.:
1988.
p.3336
<A NAME="RZ12603SS-23B">23b</A>
Sweet DV.
Registry of Toxic Effects of Chemical Substances 1985-86
U. S. Govt. Printing Office;
Washington D. C.:
1988.
p.4049
<A NAME="RZ12603SS-24">24</A>
Buckler SA.
J. Am. Chem. Soc.
1962,
84:
3093
<A NAME="RZ12603SS-25">25</A>
Olah GA.
Prakash GKS.
Superacids
Wiley;
New York:
1985.
<A NAME="RZ12603SS-26">26</A>
Chakraborti AK.
Gulhane R.
Tetrahedron Lett.
2003,
44:
3521
<A NAME="RZ12603SS-27">27</A>
Chakraborti AK.
Gulhane R.
Chem. Commun.
2003,
1896
<A NAME="RZ12603SS-28">28</A>
Aldrich (India) 2003-2004 price (US $): Cu(BF4)2·xH2O (250 g, 107.80), In(OTf)3 (50 g, 417.00), Cu(OTf)2 (50 g, 416.00), Sc(OTf)3 (50 g, 1755.00), Sc(NTf2)3 (50 g, 3000.00), Ce(OTf)3 (? g, 421.50), LiOTf (100 g, 146.20). Estimated price (not being commercially available)
(US $): Bi(OTf)3·xH2O (50 g, >315.95).
<A NAME="RZ12603SS-29">29</A>
Requirement of Ac2O(equiv): Sc(OTf)3 (1.5-as solvent), Sc(NTf2)3 (1.5), clays (2.0), zeolite (2.0), TMSOTf (1.5-as solvent), Cu(OTf)2 (2.0), Bi(OTf)3 (1.5-10), LiClO4 (2-10), Ce(OTf)3 (1.5), and LiOTf (5-8). Cu(BF4)2·xH2O(1).
<A NAME="RZ12603SS-30">30</A>
Requirement of high temperatures: Ytria-zirconia (80 °C), clays (40-80 °C), zeolite
(60 °C), and LiClO4 (r.t.-40 °C). Low temperature required for acid-sensitive substrates: Cu(OTf)2 (-25 to 0 °C), Sc(OTf)3 (-50 to -20 °C), and TMSOTf (-10 °C). Cu(BF4)2·xH2O (r.t.).
<A NAME="RZ12603SS-31">31</A>
Requirement of longer times: Sc(OTf)3 (0.5-5 h), Sc(NTf2)3 (1 h), clays (2.5 h), zeolite (1.5-12 h), Cu(OTf)2 (1-2 h), Bi(OTf)3 (1-8.5 h), ytria-zirconia (2-15 h), LiClO4 (4-48 h), Ce(OTf)3 (0.2-24 h), and LiOTf (11-30 h). Cu(BF4)2·xH2O (0.25-1 h).
<A NAME="RZ12603SS-32">32</A>
Requirement of solvents: Sc(OTf)3 (MeCN or Ac2O); Sc(NTf2)3 (MeCN); clays (CH2Cl2 or CHCl3); ytria-zirconia (MeCN); TMSOTf (CH2Cl2, MeCN-EtOAc, Ac2O); Cu(OTf)2 (MeCN), Bi(OTf)3 (MeCN, THF, toluene, CH2Cl2), and Ce(OTf)3 (MeCN). Cu(BF4)2·xH2O (under neat conditions).
<A NAME="RZ12603SS-33">33</A>
Garrett RL. In Designing Safer Chemicals American Chemical Society Symposium Series 640
Chap. 1:
Garrett RL.
De Vito SC.
American Chemical Society;
Washington D.C.:
1996.
