(dt, J 10.7, 4.4, major-O᎐CH), 4.52 (dt, J 10.7, 4.4, minor-
O᎐CH) and 7.22–7.41 (m, 5 H) [Found (HRMS): Mϩ, 316.2036.
C20H28O3 requires M, 316.2039]; trans-11 (diastereoisomeric
mixture): δH(270 MHz, CDCl3) 0.77–2.05 (m, 21 H), 3.44 (s,
minor-2-H), 3.45 (s, major-2-H), 4.84 (dt, J 10.7, 4.4, minor-
O᎐CH), 4.87 (dt, J 10.7, 4.4, major-O᎐CH) and 7.24–7.38 (m, 5
H) [Found (HRMS) Mϩ, 316.2030. C20H28O3 requires M,
316.2039].
data of 14 were in accord with those of the literature:3b δH(270
MHz, CDCl3) 0.75 (d, J 6.8, 3 H), 0.90 (d, J 6.8, 3 H), 0.91 (d,
J 6.8, 3 H), 0.97–1.14 (m, 3 H), 1.36 (s, 3 H), 1.43 (s, 3 H), 1.44–
1.54 (m, 2 H), 1.64–1.74 (m, 2 H), 1.81–1.94 (m, 1 H), 1.95–2.05
(m, 1 H), 3.32 (s, 1 H) and 4.83 (dt, J 11.2, 4.4, 1 H); for the
minor diastereoisomer: δH(270 MHz, CDCl3) 0.77 (d, J 6.8,
3 H), 0.91 (d, J 6.8, 3 H), 0.91 (d, J 6.8, 3 H), 0.94–1.14 (m, 3 H),
1.32–1.63 (m, 2 H), 1.38 (s, 3 H), 1.43 (s, 3 H), 1.64–1.73 (m,
2 H), 1.80–1.91 (m, 1 H), 1.92–2.05 (m, 1 H), 3.33 (s, 1 H) and
4.80 (dt, J 11.2, 4.4, 1 H).
(؊)-8-Phenylmenthyl 3,3-dimethyloxirane-2-carboxylate 15.
The general procedure was followed using ButOK (38 mg, 0.34
mmol), 3a (101 mg, 0.33 mmol) and acetone (0.05 ml, 0.7
mmol). Preparative TLC (silica gel, hexane–AcOEt, 13:1)
afforded 15 as a mixture of diastereoisomers in the form of a
colourless oil (70 mg, 64%; 87% de): for the major diastereo-
isomer: δH(270 MHz, CDCl3) 0.77–1.15 (m, 3 H), 0.87 (d, J 6.4,
3 H), 1.23 (s, 3 H), 1.31 (s, 3 H), 1.33 (s, 3 H), 1.37 (s, 3 H), 1.40–
1.65 (m, 3 H), 1.92–2.00 (m, 1 H), 2.06 (ddd, J 12.2, 10.8, 3.4,
1 H), 2.84 (s, 1 H), 4.87 (dt, J 10.8, 4.4, 1 H), 7.12–7.29 (m, 5 H)
[Found (HRMS): Mϩ, 330.2229. C21H30O3 requires M,
330.2195].
(؊)-8-Phenylmenthyl 3,3-dimethyloxirane-2-carboxylate 16.
The general procedure was followed using ButOK (36 mg, 0.32
mmol), 3a (99 mg, 0.32 mmol) and pentan-3-one (0.05 ml, 0.5
mmol). Preparative TLC (silica gel, hexane–AcOEt, 13:1) of
the crude product afforded 16 as a mixture of diastereoisomers
in the form of a colourless oil (54 mg, 47%; 81% de): for the
major diastereoisomer; δH(270 MHz, CDCl3) 0.73–1.09 (m,
3 H), 0.86 (d, J 6.8, 3 H), 0.89, (t, J 7.3, 3 H), 1.00 (t, J 7.3, 3 H),
1.25 (s, 3 H), 1.34 (s, 3 H), 1.39–1.75 (m, 3 H), 1.63 (q, J 7.3,
2 H), 1.67 (q, J 7.3, 2 H), 1.94–2.04 (m, 1 H), 2.01 (ddd, J 12.2,
10.7, 3.4, 1 H), 3.00 (s, 1 H), 4.87 (dt, J 10.7, 4.4, 1 H) and 7.12–
7.29 (m, 5 H) [Found: Mϩ, 358.2531. C21H34O3 requires M,
358.2508].
(؊)-8-Phenylmenthyl 3-methyl-3-phenyloxirane-2-carboxylate
12. The general procedure was followed using ButOK (74 mg,
0.66 mmol), 3a (201 mg, 0.65 mmol) and acetophenone (0.15
ml, 1.3 mmol). Preparative TLC (silica gel, hexane–AcOEt, 8:1)
of the crude product gave cis-12 (major diastereoisomer), trans-
12 (major diastereoisomer) and trans-12 (minor diastereo-
isomer) as the pure samples and all as colourless oils (201 mg,
79%; cis/trans 7.6:1.0, cis: 93% de, trans: 52% de). Use of 3b
(150 mg, 0.43 mmol) under the reaction conditions [ButOK (49
mg, 0.44 mmol) acetophenone (0.05 ml, 0.4 mmol)], gave cis-
and trans-12 as a mixture of diastereoisomers in the form of a
colourless oil (94 mg, 56%, cis/trans 5.6:1.0, cis: >95% de, trans:
21% de): cis-12 (major diasteroisomer): δH(270 MHz, CDCl3)
0.30 (q, J 12.2, 1 H), 0.61–1.21 (m, 4 H), 0.67 (d, J 6.4, 3 H),
1.10 (s, 3 H), 1.25 (s, 3 H), 1.37–1.47 (m, 2 H), 1.67 (s, 3 H),
1.75–1.83 (m, 1 H), 3.31 (s, 1 H), 4.50 (dt, J 10.7, 4.4, 1 H) and
7.13–7.40 (m, 10 H); δC(68 MHz, CDCl3) 21.4, 24.6, 25.6, 26.6,
27.4, 30.9, 34.2, 40.4, 50.1, 60.6, 63.2, 125.2, 125.5, 126.6, 127.7,
127.8, 127.9, 128.2, 137.1, 150.5 and 166.4 [Found (HRMS):
Mϩ, 392.2371. C26H32O3 requires M, 392.2351]; trans-12 (major
diastereoisomer): δH(270 MHz, CDCl3) 0.30 (q, J 12.2, 1 H),
0.61–1.21 (m, 4 H), 0.67 (d, J 6.4, 3 H), 1.10 (s, 3 H), 1.25 (s,
3 H), 1.34–1.47 (m, 2 H), 1.67 (s, 3 H), 1.75–1.83 (m, 1 H), 3.31
(s, 1 H), 4.50 (dt, J 10.7, 4.4, 1 H) and 7.13–7.40 (m, 10 H);
δC(68 MHz, CDCl3) 17.3, 21.7, 26.0, 26.8, 27.3, 31.3, 34.4, 40.0,
41.7, 50.4, 61.5, 61.8, 76.3, 125.3, 125.4, 127.9, 128.0, 128.4,
140.3, 150.7 and 166.9 [Found (HRMS): Mϩ, 392.2335. C26-
H32O3 requires M, 392.2351]; trans-12 (minor diastereoisomer):
δH(270 MHz, CDCl3) 0.85–1.88 (m, 7 H), 0.89 (d, J 6.4, 3 H),
1.22 (s, 3 H), 1.34 (s, 3 H), 1.63 (s, 3 H), 2.02–2.11 (m, 1 H), 2.32
(s, 1 H), 4.96 (dt, J 10.7, 4.4, 1 H), 7.01–7.07 (m, 1 H) and 7.18–
7.37 (m, 9 H) [Found: (HRMS): Mϩ, 392.2365. C26H32O3
requires M, 392.2351.
(؊)-8-Phenylmenthyl 3-ethyl-3-phenyloxirane-2-carboxylate
13. The general procedure was followed using ButOK (37 mg,
0.33 mmol), 3a (101 mg, 0.33 mmol) and propiophenone (0.05
ml, 0.4 mmol). Preparative TLC (silica gel, hexane–AcOEt,
13:1) afforded cis-13 and trans-13 as a mixture of diastereo-
isomers in the form of a colourless oil (63 mg, 47%; cis/trans
4.5:1.0, cis: 87% de, trans: 78% de). Use of 3b (94 mg, 0.26
mmol) under the reaction conditions [BttOK (33 mg, 0.30
mmol) and propiophenone (0.05 ml, 0.4 mmol)], gave cis- and
trans-13 as a mixture of diastereoisomers in the form of a
colourless oil (46 mg, 43%; cis/trans 4.2:1.0, cis: >95% de,
trans: >95% de): cis-13 (diastereoisomeric mixture): δH(270
MHz,CDCl3) 0.20 (q, J 12.5, 1 H), 0.58–1.45 (m, 6 H), 0.65
(d, J 6.4, 3 H), 0.88 (t, J 7.3, 3 H), 1.14 (s, 3 H), 1.28 (s, 3 H),
1.65–1.80 (m, 2 H), 2.17 (dq, J 14.7, 7.3, 1 H), 3.36 (s, 1 H), 4.49
(dt, J 10.6, 4.4, 1 H) and 7.13–7.37 (m, 10 H) [Found (HRMS):
Mϩ, 406.2537. C27H34O3 requires M, 406.2508]; trans-13 (dia-
stereoisomeric mixture): δH(270 MHz, CDCl3) 0.77–1.56 (m, 6
H), 0.87 (d, J 6.4, 3 H), 0.95 (t, J 7.3, 3 H), 1.29 (s, 3 H), 1.39
(s, 3 H), 1.85–2.05 (m, 3 H), 2.17 (dq, J 14.2, 7.3, 1 H), 3.16
(s, 1 H), 4.89 (dt, J 14.2, 4.1, 1 H), 7.04–7.10 (m, 1 H) and 7.20–
7.38 (m, 9 H) [Found (HRMS): Mϩ, 406.2537. C27H34O3
requires M, 406.2508].
(؊)-8-Phenylmenthyl
spiro[cyclopentane-1,2Ј-oxirane]-3Ј-
carboxylate 17. The general procedure was followed using
ButOK (34 mg, 0.30 mmol), 3a (91 mg, 0.29 mmol) and
cyclopentanone (0.05 ml, 0.6 mmol). Preparative TLC (silica
gel, hexane–AcOEt, 13:1) of the crude product afforded 17 as a
mixture of diastereoisomers in the form of a colourless oil (49
mg, 45%; 80% de): for the major diastereoisomer: δH(270 MHz,
CDCl3) 0.77–1.14 (m, 3 H), 0.87 (d, J 6.3, 3 H), 1.23 (s, 3 H),
1.31 (s, 3 H), 1.40–2.00 (m, 4 H), 1.57–1.62 (m, 2 H), 1.62–1.66
(m, 2 H), 1.76–1.87 (m, 4 H), 2.05 (ddd, J 12.2, 10.7, 2.9, 1 H),
3.01 (s, 1 H), 4.86 (dt, J 12.2, 10.7, 4.4, 1 H) and 7.12–7.28 (m,
5 H) [Found (HRMS): Mϩ, 356.2346. C23H32O3 requires M,
356.2352].
(؊)-8-Phenylmenthyl
spiro[cyclohexane-1,2Ј-oxirane]-3Ј-
carboxylate 18. The general procedure was followed using
ButOK (36 mg, 0.32 mmol), 3a (93 mg, 0.30 mmol) and
cyclohexanone (0.05 ml, 0.5 mmol). Preparative TLC (silica gel,
hexane–AcOEt, 13:1) of the crude product afforded 18 as a
mixture of diastereoisomers in the form of a colourless oil (50
mg, 45%; 96% de): for the major diastereoisomer: δH(270 MHz,
CDCl3) 0.74–1.10 (m, 3 H), 0.86 (d, J 6.8, 3 H), 1.24 (s, 3 H),
1.24–1.34 (m, 2 H), 1.34 (s, 3 H), 1.37–1.75 (m, 3 H), 1.52–1.57
(m, 2 H), 1.65–1.72 (m, 6 H), 1.93–2.02 (m, 1 H), 2.02 (ddd,
J 12.2, 10.7, 3.4, 1 H), 2.96 (s, 1 H), 4.88 (dt, J 10.7, 4.4, 1 H)
and 7.13–7.30 (m, 5 H); δC(68 MHz, CDCl3) 21.5, 24.4, 24.6,
25.1, 25.6, 26.7, 27.4, 28.2, 31.1, 34.2, 34.7, 39.8, 41.4, 50.1,
59.2, 64.4, 75.8, 125.0, 125.2, 127.7, 150.5 and 167.3 [Found
(HRMS): Mϩ, 370.2543. C24H34O3 requires M, 370.2508].
(؊)-8-Phenylmenthyl 3,3-dimethyloxirane-2-carboxylate 19.
The general procedure was followed using ButOK (39 mg, 0.35
mmol), 3a (107 mg, 0.35 mmol) and benzophenone (92 mg, 0.50
mmol). Preparative TLC (silica gel, hexane–AcOEt, 13:1) of
the crude product afforded 19 as a mixture of diastereoisomers
in the form of a colourless oil (71 mg, 45%; 77% de): for the
major diastereoisomer: δH(270 MHz, CDCl3) 0.28 (q, J 12.2,
(؊)-Menthyl 3,3-dimethyloxirane-2-carboxylate 14. The gen-
eral procedure was followed using ButOK (34 mg, 0.31 mmol),
2a (0.1 ml, 0.43 mmol) and acetone (0.05 ml, 0.7 mmol). Pre-
parative TLC (silica gel, hexane–AcOEt, 13:1) afforded 14 as a
mixture of diastereoisomers in the form of a colourless oil (30
mg, 39%, 14% de). For the major diastereoisomer, the 1H NMR
696
J. Chem. Soc., Perkin Trans. 1, 1998