8
218 J . Org. Chem., Vol. 64, No. 22, 1999
Marshall and Grant
ford nearly 1:1 mixtures of anti,syn and anti,anti
diastereomers.
samarium19 intermediates may proceed through an analo-
gous pathway. The present process is particularly note-
worthy by virtue of the high degree of enantioselectivity
attending the transmetalation and the high degree of
reagent control exhibited in the additions to R-chiral
aldehydes.13
3
b
Exp er im en ta l Section
Two sources of InI were employed in these studies. The
commercial material comes in the form of small spheres
that were crushed prior to use to increase surface area
In d iu m (III) Iod id e. To a 1 L, oven-dried, round-bottomed
flask flushed with argon and equipped with a magnetic stirrer
was added xylenes (500 mL). The solvent was degassed and
the flask equipped with a reflux condenser. Indium powder
7
and reactivity. Alternatively, InI can be prepared by
(eq 8).15 Material
2
reaction of indium metal with I
(
5.00 g, 43.55 mg-atoms) was added followed by iodine (16.57
g, 65.32 mmol). The mixture was vigorously stirred and
refluxed (bath temperature ∼160-170 °C) under argon for
1
-1.5 h or until the indium metal was consumed. If the metal
was not fully consumed, a crystal of iodine was added, and
stirring at reflux was resumed. The reaction was considered
complete when the added iodine was not consumed after 15
min at reflux. The solution was hot filtered with suction and
allowed to cool to room temperature. The resulting bright
yellow crystals were filtered and washed with two 10-mL
prepared in this way is isolated as a highly reactive
powder that can be used directly. Our preparation differs
somewhat from the published version in stoichiometry
portions of cold benzene to remove traces of I
was concentrated to 1/4-1/3 volume and cooled to 0 °C. The
yellow crystals of InI were filtered and washed with cold
2
. The filtrate
3
and ease of execution. The InI formed in the second step
3
of the reaction sequence can be recycled with no loss of
yield. A one-step conversion of In to InI is not possible
because the actual product from step two of eq 8 is a
benzene (10 mL). The product was dried in vacuo to yield 18.30
g (85%) of indium(III) iodide as a fine yellow powder. Note:
indium(III) iodide is very hygroscopic.
In d iu m (I) Iod id e. To a 1 L, oven-dried, round-bottomed
flask flushed with argon and equipped with a magnetic stirrer
was added xylenes (400 mL). The solvent was degassed, and
the flask was equipped with a reflux condenser. Indium(III)
iodide (18.30 g, 36.93 mmol) was added to the flask followed
by indium powder (2.12 g, 18.46 mmol). The mixture was
vigorously stirred at reflux under argon for 18 h. The resulting
yellow suspension was allowed to cool to room temperature,
diluted with ether (400-500 mL), and stirred for 1 h. The
resulting burgundy precipitate was filtered and washed with
ether (100 mL). The product was dried in vacuo to yield 6.14
g (92%) of indium(I) iodide. The filtrate was concentrated to
dryness to yield 14.43 g (105%) of recovered indium(III) iodide
as a fine yellow powder.
stable complex, In(InI
of ether to form a mixture of insoluble InI and a soluble
InI complex. Most of the addition reactions with InI were
4
), which is broken up by addition
3
performed with the commercial material because we did
not examine the noncommercial material until relatively
late in our studies. However, we have repeated the
preparation of adduct 14 numerous times on various
scales with consistent results, which suggests that both
sources of InI will give comparable results for all systems
studied. We have included an Organic Synthesis-type
procedure for InI and adduct 14 in the Experimental
Section. It is possible to regenerate In metal by electroly-
sis of the water soluble salts recoverd after isolation of
the aldehyde allenyl indium adduct by extraction.16 This
option might be desireable for large-scale applications.
However, we did not explore that methodology in the
present work.
(R)-3-Bu tyn -2-ol Meth a n esu lfon a te (7). To a 1 L, oven-
dried, round-bottomed flask flushed with argon and equipped
with a magnetic stirrer were added CH Cl (713 mL) and (R)-
2 2
(
+)-3-butyn-2-ol (10.00 g, 0.143 mol). The mixture was cooled
3
to -78 °C, and Et N (39.66 mL, 0.285 mol) and methane-
sulfonyl chloride (16.56 mL, 0.214 mol) were added. The
A possible catalytic cycle for the Pd/In metathesis
reaction is depicted in eq 9. The overall process may be
viewed as an oxidative transmetalation. The reported in
situ generation of allylic zinc,17 allylic tin, and allylic
resulting mixture was stirred at -78 °C for 1 h, quenched with
saturated NaHCO solution, and allowed to warm to room
3
temperature. The layers were separated, and the organic layer
was washed with brine and concentrated under aspirator
pressure. The residue was diluted with 500 mL of ether and
washed with water followed by brine. The aqueous layer was
extracted with ether. The combined extracts were dried over
18
(
(
15) Freeland, B. H.; Tuck, D. G. Inorg. Chem. 1976, 15, 475.
16) Tokuda, M.; Satoh, S.; Katoh, Y.; Suginome, H. Electrochemical
Synthesis; Little, R. D., Weinberg, N. L., Eds.; Dekker: New York,
2 4
anhydrous Na SO and concentrated under aspirator pressure
to yield 20.13 g (95%) of methanesulfonate 7. The material
1
6
991; p 83. Cited in: Paquette, L. A.; Lobben, P. C. J . Org. Chem. 1998,
3, 5604.
(
17) Masuyama, Y.; Kinugawa, N.; Kurusu, Y. J . Org. Chem. 1987,
2, 3702. Qui, W.; Wang, Z. J . Chem. Soc., Chem. Commun. 1989, 356.
18) Takahara, J . P.; Masuyama, Y.; Kurusu, Y. J . Am. Chem. Soc.
992, 114, 2577.
5
(19) Tabuchi, T.; Inanaga, J .; Yamaguchi, M. Tetrahedron Lett. 1987,
28, 215. Tabuchi, T.; Inanaga, J .; Yamaguchi, M. Tetrahedron Lett.
1986, 27, 1195.
(
1