G. Bartoli, M. Bosco, R. Dalpozzo, E. Marcantoni, M. Massaccesi, L. Sambri
FULL PAPER
300 MHz with a Varian Gemini instrument. 13C NMR and DEPT
experiments were acquired at 75 MHz with a Varian Gemini instru-
ment. Chemical shifts are given in ppm from Me4Si. Coupling con-
stants are given in Hertz (Hz). All the reactions were monitored by
GC/MS, starting from 10 min after the mixing of the reagents.
δ ϭ 20.9 (CH3), 25.8 (CH2), 28.0 (CH2), 28.5 (CH2), 28.6 (CH2),
29.0 (CH2), 29.2 (CH2), 32.7 (CH2), 33.9 (CH2), 64.5 (CH2),
171.1 (C).
(2,2-Dimethyl-1,3-dioxolan-4-yl)methyl Acetate (25b): Yield
Ͼ
99 %, 1.73 g starting from (1.32 g, 10 mmol) of 25a. 1H NMR
(CDCl3, 300 MHz, ppm): δ ϭ 1.31 (s, 3 H, CH3), 1.39 (s, 3 H,
CH3), 2.05 (s, 3 H, CH3), 3.60Ϫ3.75 (m, 1 H), 3.95Ϫ4.15 (m, 3 H),
4.20Ϫ4.35 (m, 1 H). 13C NMR (CDCl3, 75 MHz, ppm): δ ϭ 20.7
(CH3), 25.3 (CH3), 26.6 (CH3), 64.8 (CH2), 66.2 (CH2), 73.5 (CH),
109.8 (C), 170.8 (C).
Acetylation of 2-Phenylethanol (1a) with Ac2O: To a round-bot-
tomed flask were added 1a (10 mmol) and an acetic anhydride solu-
tion of the catalyst (1 mL), prepared from the appropriate amount
of the chosen perchlorate and 10 mL of Ac2O (Table 1, Entries
1Ϫ6). In addition, Ac2O (8.5 mL) was added in the reactions of
Entries 7 and 8. The mixture was stirred at 20 °C until the reaction
was complete. After Et2O and aqueous NaHCO3 had been added,
the mixture was stirred for 30 min to decompose the excess Ac2O.
The aqueous layer was separated and extracted with Et2O. The
combined organic layers were dried with MgSO4 and the solvent
was evaporated to give the pure acetate 1b.
(1SR,2SR)-3-(Dimethylamino)-1-ethyl-2-methyl-1-phenylpropyl
Acetate (26b): Yield 95 %, 0.25 g starting from (0.22 g, 1 mmol) of
26a. 1H NMR (CDCl3, 300 MHz, ppm): δ ϭ 0.72 (t, 3 H, CH3,
JH,H ϭ 7.2), 0.78 (d, 3 H, CH3, JH,H ϭ 7.1), 1.55Ϫ1.70 (m, 1 H),
1.95Ϫ2.05 (m, 1 H), 2.09 (s, 3 H, CH3), 2.11 (s, 6 H, 2CH3),
2.45Ϫ2.70 (m, 3 H), 7.15Ϫ7.30 (m, 5 H, Ph). 13C NMR (CDCl3,
75 MHz, ppm): δ ϭ 8.0 (CH3), 13.5 (CH3), 22.1 (CH), 26.8 (CH2),
37.4 (CH3), 45.9 (CH3), 62.6 (CH2), 90.0 (C), 126.3 (CH), 126.8
(CH), 127.5 (CH), 140.0 (C), 169.8 (C).
Acetylation of 1-Adamantanol (2a) with Ac2O: To a round-bot-
tomed flask were added 2a (10 mmol) and 1 mL of a 10Ϫ3 acetic
anhydride solution of Zn(ClO4)·6H2O and the calculated amount
of the chosen solvent. The mixture was stirred at 20 °C until the
reaction was complete. After Et2O and aqueous NaHCO3 had been
added, the mixture was stirred for 30 min to decompose the slight
excess of Ac2O. The aqueous layer was separated and extracted
with Et2O. The combined organic layers were dried with MgSO4
and the solvent was evaporated to give the pure acetate 2b.
(Z)-4-Oxo-4-(phenethyloxy)-2-butenoic Acid (1h): Yield 75 %,
1.65 g starting from (1.22 g, 10 mmol) of 1a. 1H NMR (CDCl3,
300 MHz, ppm): δ ϭ 3.02 (t, 2 H, CH2, JH,H ϭ 7.4), 4.48 (t, 2 H,
CH2, JH,H ϭ 7.4), 6.35 (d, 1 H, CH, JH,H ϭ 12.6), 6.43 (d, 1 H,
CH, JH,H ϭ 12.6), 7.20Ϫ7.40 (m, 5 H, Ph). 13C NMR (CDCl3,
75 MHz, ppm): δ ϭ 34.5 (CH2), 66.7 (CH2), 126.7 (CH), 128.5
(CH), 128.7 (CH), 130.0 (CH), 133.7 (CH), 136.8 (C), 166.2 (C),
166.8 (C).
Zn(ClO4)·6H2O-Catalyzed Acetylation of Alcohols with Ac2O
(General Procedure): The substrate (10 mmol) was added dropwise
when liquid, or in small portions when solid, to 1 mL of a 10Ϫ3
(E)-3-Hexenyl Pivalate (15c): Yield Ͼ 99 %, 1.83 g starting from
acetic anhydride solution of Zn(ClO4)·6H2O. The mixture was
stirred at 20 °C until the reaction was complete. After Et2O and
aqueous NaHCO3 had been added, the mixture was stirred for
30 min to decompose the slight excess of Ac2O. The aqueous layer
was separated and extracted with Et2O. The combined organic lay-
ers were dried with MgSO4 and the solvent was evaporated to give
the pure acetates.
1
(1.00 g, 10 mmol) of 15a. H NMR (CDCl3, 300 MHz, ppm): δ ϭ
0.95 (t, 3 H, CH3, JH,H ϭ 7.4), 1.19 (s, 9 H, 3CH3), 1.90Ϫ2.05 (m,
2 H, CH2), 2.35Ϫ2.45 (m, 2 H, CH2), 4.05 (t, 2 H, CH2, JH,H
ϭ
6.7), 5.30Ϫ5.40 (m, 1 H, CH), 5.45Ϫ5.60 (m, 1 H, CH). 13C NMR
(CDCl3, 75 MHz, ppm): δ ϭ 13.7 (CH3), 25.6 (CH2), 27.2 (CH3),
32.0 (CH2), 38.7 (C), 63.8 (CH2), 124.2 (CH), 134.9 (CH), 178.6
(C).
Zn(ClO4)·6H2O-Catalyzed Acylation of Alcohols with Anhydrides
(Representative Procedure): To a round-bottomed flask were added
2-phenylethanol (1a) (1.22 g, 10 mmol), Zn(ClO4)·6H2O (37 mg,
0.1 mmol), benzoic anhydride (2.38 g, 10.5 mmol) and Et2O
(3.15 mL, 30 mmol). The mixture was heated at reflux for 1 h, and
then cooled to room temperature. After Et2O and aqueous
NaHCO3 had been added, the mixture was stirred for 30 min to
decompose the slight excess of (PhCO)2O. The aqueous layer was
separated and extracted with Et2O. The combined organic layers
were dried with MgSO4 and the solvent was evaporated to give the
pure ester 1f (2.25 g, yield Ͼ 99 %). Spectroscopic data of com-
pounds not found in the literature:
4-[(E)-3-Hexenyloxy]-4-oxobutanoic Acid (15d): Yield Ͼ 99 %,
1.99 g starting from (1.00 g, 10 mmol) of 15a. 1H NMR (CDCl3,
300 MHz, ppm): δ ϭ 0.94 (t, 3 H, CH3, JH,H ϭ 7.5), 1.90Ϫ2.05
(m, 2 H, CH2), 2.20Ϫ2.35 (m, 2 H, CH2), 2.55Ϫ2.65 (m, 4 H, 2
CH2), 4.05Ϫ4.10 (m, 2 H, CH2), 5.25Ϫ5.40 (m, 1 H, CH),
5.45Ϫ5.65 (m, 1 H, CH), 7.9 (br. s, 1 H, OH). 13C NMR (CDCl3,
75 MHz, ppm): δ ϭ 13.7 (CH3), 25.5 (CH2), 28.8 (CH2), 28.9
(CH2), 31.8 (CH2), 64.4 (CH2), 123.8 (CH), 135.2 (CH), 172.1 (C),
177.7 (C).
4-[(Z)-3-Hexenyloxy]-4-oxobutanoic Acid (16c): Yield Ͼ 99 %,
1.99 g starting from (1.00 g, 10 mmol) of 16a. 1H NMR (CDCl3,
300 MHz, ppm): δ ϭ 0.94 (t, 3 H, CH3, JH,H ϭ 7.5), 1.95Ϫ2.10
(m, 2 H, CH2), 2.30Ϫ2.40 (m, 2 H, CH2), 2.55Ϫ2.70 (m, 4 H, 2
CH2), 4.00Ϫ4.10 (m, 2 H, CH2), 5.20Ϫ5.35 (m, 1 H, CH),
5.45Ϫ5.55 (m, 1 H, CH). 13C NMR (CDCl3, 75 MHz, ppm): δ ϭ
14.1 (CH3), 20.5 (CH2), 26.6 (CH2), 28.7 (CH2), 28.9 (CH2), 64.3
(CH2), 123.4 (CH), 134.6 (CH), 172.1 (C), 178.2 (C).
Methyl (2S)-3-(Acetyloxy)-2-methylpropanoate (21b): Yield Ͼ 99 %,
0.64 g starting from (0.47 g, 4 mmol) of 21a. 1H NMR (CDCl3,
300 MHz, ppm): δ ϭ 1.21 (d, 3 H, CH3, JH,H ϭ 7.2), 2.05 (s, 3 H,
CH3), 2.70Ϫ2.90 (m, 1 H, CH), 3.71 (s, 3 H, CH3), 4.13 (dd, 1 H,
CH2, JH,H ϭ 10.7, JH,H ϭ 5.7), 4.20 (dd, 1 H, CH2, JH,H ϭ 10.7,
JH,H ϭ 7.2). 13C NMR (CDCl3, 75 MHz, ppm): δ ϭ 13.5 (CH3),
20.5 (CH3), 38.7 (CH3), 51.6 (CH), 65.2 (CH2), 170.4 (C), 174.0
(C).
Acknowledgments
9-Bromononyl Acetate (23b): Yield Ͼ 99 %, 0.53 g starting from Work carried out in the framework of the National Project ‘‘Stereo-
1
(0.45 g, 2 mmol) of 23a. H NMR (CDCl3, 300 MHz, ppm): δ ϭ
1.35Ϫ1.50 (m, 10 H, CH2), 1.50Ϫ1.70 (m, 2 H, CH2), 1.75Ϫ1.95 ported by MIUR, Rome, and by the University of Bologna, in the
(m, 2 H, CH2), 2.05 (s, 3 H, CH3), 3.41 (t, 2 H, CH2, JH,H ϭ 6.8), framework of ‘‘Progetto di Finanziamento Pluriennale, Ateneo di
4.05 (t, 2 H, CH2, JH,H ϭ 6.7). 13C NMR (CDCl3, 75 MHz, ppm): Bologna’’.
selezione in Sintesi Organica, Metodologie e Applicazioni’’ sup-
4616
2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2003, 4611Ϫ4617