Stereoselective synthesis of axially chiral natural products, (-)- steganone and O,O'-dimethylkorupensamine A, utilizing planar chiral (arene)chromium complexes

TETRAHEDRON

Pergamon

Tetrahedron 56 (2000) 2325±2337

Stereoselective Synthesis of Axially Chiral Natural Products,

(2)-Steganone and O,O⁰-Dimethylkorupensamine A, Utilizing

Planar Chiral (Arene)chromium Complexes

Ken Kamikawa,^aTakashi Watanabe,^aAkira Daimon^band Motokazu Uemura^a,

*

^aDepartment of Chemistry, Faculty of Integrated Arts & Sciences, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan

^bDainippon Ink and Chemicals, Inc., Suita, Osaka 564-0011, Japan

Accepted 7 December 1999

AbstractÐPalladium(0)-mediated Suzuki±Miyaura cross-coupling of planar chiral (2,6-disubstituted bromobenzene)chromium complexes

with o-substituted arylboronic acids in the presence of sodium carbonate under re¯uxing in aqueous methanol gave stereoselectively axially

chiral mono Cr(CO)₃-complexed biaryls. The axial stereochemistry of the cross-coupling products was found to be largely dependent on the

steric bulkiness of ortho substituent of arylboronic acids and reaction conditions. The cross-coupling with o-alkyl or hydroxymethyl

substituted arylboronic acids gave kinetically controlled products in which the ortho substituents were oriented in syn-con®guration to

the tricarbonylchromium fragment. On the other hand, o-formyl phenylboronic acid produced thermodynamically stable anti-coupling

products under the same conditions. By utilizing these methodologies, biologically active axially chiral natural products, (2)-steganone

and O,O⁰-dimethyl derivative of the natural product of korupensamine A, were stereoselectively synthesized. q 2000 Elsevier Science Ltd.

Introduction

stereocontrolled torsion of ¯at achiral lactone precursors

by means of optically active nucleophiles.⁷Other interesting

methods including catalytic asymmetric coupling⁸have

been reported to prepare biaryls in optically active form.

Axially chiral biaryls are of importance not only as chiral

ligands or auxiliaries in asymmetric reactions but also for

the synthesis of biologically active natural products. There

is a considerable current interest in the development of

ef®cient methodologies for the synthesis of biaryls with

atropisomers in an enantiomerically pure form.¹Nucleo-

philic displacement of an ortho methoxy group of chiral

aryl oxazolines with aryl Grignard reagents has been widely

employed in the asymmetric biaryl syntheses.²Copper-

mediated Ullmann homo-coupling reaction has recently

been observed for biaryl coupling of the chiral ortho

bromo phenyloxazolines.³Nucleophilic aromatic substi-

tution to the arene ring activated with other functional

groups, e.g. ester, imine, has also been achieved for the

preparation of chiral biaryl compounds.⁴For an intra-

molecular aryl coupling reaction⁵giving lignans and the

related compounds, the bridge containing a chiral part is

not only a constituent part of the target molecular but also

at the same time it determines the steric course of the

coupling reaction. Cyanocuprate mediated biaryl intra-

molecular coupling of a tethered nonracemic chiral

compound is also elaborated.⁶Atrop-enantioselective biaryl

synthesis as an unique method has been achieved by

(h⁶-Polysubstituted arene)chromium complexes exist in two

enantiomeric forms based on a planar chirality when the

arene ring is substituted at ortho- or meta-positions with

different substituents. This fact in concert with ability of

the tricarbonylchromium function to effectively block one

face of the arene ring, has led to a rapid increase in the use of

(arene)chromium complexes as the synthetic intermediates⁹

and as the catalysts¹⁰for the asymmetric reactions. As part

of our asymmetric exploration of the planar chiral arene

chromium complexes, we have developed diastereoselec-

tive synthesis of axially chiral biaryls in enantiomerically

pure form. In this paper, we wish to report further appli-

cation of the palladium(0)-catalyzed cross-coupling of

planar chiral arylhalide chromium complexes with aryl-

boronic acids to the synthesis of biologically active axially

chiral natural product and its derivative, (2)-steganone and

O,O⁰-dimethylkorupensamine A.

Results and Discussion

Axially chiral biaryls utilizing planar chiral

(arene)Cr(CO)₃complexes

Keywords: alkaloids; atropisomerism; chromium and compounds; coupling

reactions.

* Corresponding author. Tel.: 181-722-54-9698; fax: 181-722-54-9931;

e-mail: uemura@ms.cias.osakafu-u.ac.jp

Cross-coupling reactions of aryl halides or aryl tri¯ates with

PII: S0040-4020(99)01115-1

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K. Kamikawa et al. / Tetrahedron 56 (2000) 2325±2337

Scheme 1. Palladium-catalyzed cross-coupling of planar chiral (arene)Cr(CO)₃complexes.

arylmetals catalyzed by palladium(0) are used for the

preparation of biaryls. An oxidative addition of the

carbon±halogen bond of the aryl halide to the palladium(0)

is accelerated by a coordination of an electron withdrawing

tricarbonylchromium fragment to the arene ring. Even

chlorobenzene can be made susceptible to oxidative

addition by utilizing the corresponding tricarbonyl-

chromium complex to give cross-coupling products.¹¹We

have already reported¹²that the palladium(0)-mediated

cross-coupling of planar chiral (o-substituted arylhalide)-

chromium complexes with o-substituted arylboronic acids

in the presence of sodium carbonate under re¯uxing in

aqueous methanol gave stereoselectively axially chiral

mono Cr(CO)₃-complexed biaryls. The axial stereo-

chemistry of the cross-coupling products was found to be

largely dependent on the nature of ortho substituent of aryl-

boronic acids and reaction conditions.

anti-biphenyl complexes under re¯uxing in higher boiling

solvents, e.g. toluene, xylene, mesitylene, since the syn-

biphenyl chromium complexes 3 are kinetically controlled

products. As the mono-Cr(CO)₃complexes of biaryls have

both axial and planar chiralities, the chromium-complexed

biaryls can exist in an enantiomerically active form based on

the planar chirality even when the central bond rotates.

Consequently, we can easily prepare both atropisomers

from a single planar chiral arene chromium complex by

utilizing this diastereoselective cross-coupling and subse-

quent axial isomerization.¹⁵

Synthesis of (2)-steganone

On the basis of above stereochemical results in the cross-

coupling of planar chiral arene chromium complexes with

arylboronic acids, we have next investigated total synthesis

of biologically active axial natural products, e.g. (2)-stega-

none and O,O⁰-dimethylkorupensamine A. (2)-Steganone

5, an antileukemic bisbenzocyclooctadiene lignan lactone,

one of four isolated¹⁶Steganotaenia araliacea by Kupchan

in 1973, has attracted considerable synthetic interest.¹⁷

These ligands have demonstrated signi®cant in vivo activity

against P-338 leukemia in mice and have displayed signi®-

cant in vitro activity against cells derived from human

carcinoma of the nasopharynx. This natural product has

the axial chirality between two phenyl rings and the chiral

center derived from trans-fused g-lactone. The novel

feature of our strategy of total synthesis of (2)-steganone

is to initially prepare an enantiomerically pure (arylhalide)-

chromium complex with planar chirality via diastereoselec-

tive ortho lithiation, and subsequently to form the axial

asymmetry of the biaryl bond (Scheme 2).¹⁸

For instance, the cross-coupling of o-alkyl, alkoxy or

hydroxymethyl substituted phenylboronic acid 2 with the

chromium complex 1 gave the syn-(S^p,S^p)-con®gurated¹³

coupling products 3 (Scheme 1). The ortho substituent R²

on the B-ring of syn-product 3 is directed toward the tricar-

bonylchromium fragment in spite of a severe steric inter-

action between Cr(CO)₃group and the ortho substituents.

On the other hand, o-formylphenylboronic acid produced

diastereoisomeric anti-(S^p,R^p)-chromium complexes 4 as the

only isolated coupling products under the same conditions.

In some cases, the CO-inserted products, benzophenone

chromium complexes were obtained in various ratios.

Similarly, a-naphthylboronic acids were reacted with

(2,6-disubstituted-1-bromobenzene)Cr(CO)₃complexes 1

under the same conditions to give the syn-coupling products

without formation of anti-isomer in good yields.¹⁴Further-

more, the syn-biphenyl chromium complexes 3 were easily

isomerized to the corresponding thermodynamically stable

Since optical resolution methods¹⁹for the preparation of

planar chiral (arene)chromium complexes waste the

Scheme 2. Retrosynthesis of (2)-steganone.

K. Kamikawa et al. / Tetrahedron 56 (2000) 2325±2337

2327

Scheme 3. Synthesis of planar chiral bromobenzene chromium complex 9. Reagents and conditions: (a) Cr(CO)₆, n-Bu₂O/THF (10/1), 1408C, 18 h, 62%; (b)

n-BuLi, toluene, 2788C, then BrCF₂CF₂Br, 54%; (c) 6H-HCl, THF, 408C, 30 min, 83%.

corresponding antipode (arene)chromium complex, we

studied diastereoselective ortho lithiation of tri-

of 9 was assigned as shown in the text by the observed

correlation with the sign of the speci®c rotations of related

(o-halogenated benzaldehyde)Cr(CO)₃complexes,^9aand by

analogy to the related diastereoselective lithiation with

ferrocene homology.²²

a

carbonyl(3,4,5-trimethoxybenzaldehyde acetal)chromium

complex for the preparation of planar chiral (arylhalide)-

chromium complex. Initially, we examined the diastereo-

selective ortho lithiation of chiral C₂symmetric acetal

complex, e.g. tricarbonylchromium complex of (4R,5R)-

[4,5-bis(a-methyl-a-methoxymethyl-2-(3⁰,4⁰,5⁰-trimethoxy-

phenyl)-1,3-dioxolane] derived from (1)-diethyl tartrate

developed by Green and co-workers.²⁰However, the dia-

stereoselective ortho lithiation followed by bromination

with 1,2-dibromo-1,1,2,2-tetra¯uoroethane gave only 33%

de in 69% yield. Therefore, we next turned our attention to

another chiral benzaldehyde acetal auxiliary (Scheme 3).

Dimethyl acetal of 3,4,5-trimethoxybenzaldehyde was

reacted with (S)-(2)-1,2,4-butanetriol derived from

l-malic acid followed by methylation with NaH/MeI to

give stereoselectively 1,3-di-equatorial substituted dioxane

structure 6 without formation of 5-membered acetal ring²¹

in 73% overall yield. Tricarbonylchromium complexation

of 6 with Cr(CO)₆under usual thermal conditions gave the

corresponding (arene)chromium complex 7 ([a]²_D⁷219.6)

in 67% yield. Diastereoselective ortho lithiation of 7 with

butyl lithium followed by bromination and subsequent

acidic hydrolysis of the acetal group afforded optically

active (1)-(2-bromo-3,4,5-trimethoxybenzaldehyde)Cr(CO)₃

(9). Diastereoselectivity of the ortho lithiation was largely

dependent upon the nature of lithiation solvent. Thus, the

ortho lithiation in polar solvent was extremely low stereo-

selectivity owing to a coordination of the lithium with

oxygen of solvent (e.g. 67% ee in ether, 3% ee in THF).

Fortunately, a use of toluene as solvent with n-BuLi for the

directed lithiation resulted in 90% ee of (1)-9. The optical

purity of 9 was increased to .99% ee ([a]²_D⁷11036) by

one fractional crystallization of the brominated acetal

compound 8 from ether/hexane and following acidic

hydrolysis of the acetal. Although the yield of brominated

product was moderate, the starting material could be easily

recovered by ¯ash chromatography before the acidic

hydrolysis step. The stereochemistry of the planar chirality

The observed diastereoselectivity for the directed ortho

lithiation of 7 could be explained as follows (Fig. 1). Both

tricarbonylchromium-complexed arene ring and methoxy-

methyl are equatorial. Among proposed transition states, a

conformer 10 has a severe steric hindrance between tricar-

bonylchromium fragment and 1,3-dioxane part, and the

other conformer 11 is free of hindrance with an exo-relation-

ship between the chromium fragment and oxygen of

dioxane. Therefore, the ortho lithiation would stereo-

selectively occur at H^a-position via a chelation of the

lithium with oxygen atoms of the conformer 11 giving the

planar chiral (1)-chromium complex 9.

With an optically active planar chiral (arene)chromium

complex in hand, the next stage of our effort was to form

stereoselectively the axial chirality by the cross-coupling

with o-substituted arylboronic acid. Reaction of (2)-(2-

bromo-3,4,5-trimethoxybenzylalcohol)chromium (12) ([a]²_D⁴

1214), derived from 9 by reduction, with 2-formyl-4,5-

methylenedioxyphenylboronic acid (13) in the presence of

5mol % of Pd(PPh₃)₄gave biaryl coupling product 14

([a]²_D⁵2161.5) in 67% yield without formation of the

corresponding atropisomer. The axial stereochemistry of

14 was assigned as (R)-con®guration on the basis of the

previous results^12b,cthat the coupling reactions of (o-substi-

tuted arene)Cr(CO)₃complexes with o-formylphenyl-

boronic acid gave stereoselectively the (R)-axial

con®guration products. At this axial juncture, the assign-

ment was purely arbitrary, but this assumption proved to

be correct as the synthesis reached its target molecule.

Furthermore, the axial stereochemistry of 14 was con®rmed

by ¹H NMR spectra of diastereomeric chromium complexes

as follows. The benzylic methylene protons of chromium-

uncomplexed ring 15 obtained by reduction with NaBH₄

Figure 1. Transition state for diastereoselective ortho lithiation.

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K. Kamikawa et al. / Tetrahedron 56 (2000) 2325±2337

Figure 2.

appeared at 4.14 and 4.24 ppm, while the corresponding

methylene of cross-coupling product 17 with 2-hydroxy-

methyl-4,5-methylenedioxyphenylboronic acid 16 under

the same conditions showed at 4.40 and 4.50 ppm as a

double doublet. Generally, NMR signals of the benzylic

proton syn to the Cr(CO)₃fragment are shifted to lower

®eld than those of the anti proton due to anisotropic effect.²³

could be easily predicted from the transition state as

shown in Fig. 2. The carbonyl oxygen of axial biphenyl-

chromium complex would be oriented anti to the chromium-

complexed phenyl ring due to steric hindrance, and methyl

lithium attack re-face of the carbonyl avoiding steric

hindrance with t-BuMe₂Si group to afford the R-con®gu-

rated secondary alcohol 18a (Scheme 4).

It was now necessary to elaborate the biaryl to the

8-membered ring present in steganone from the coupling

product 14. Protection of the hydroxyl group with t-butyl-

dimethylsilyl chloride followed by treatment with methyl-

lithium at 2788C afforded 5:1 diastereomeric mixture of

secondary alcohols 18a,b in 83% overall yield. This mixture

was cleanly separated by ¯ash chromatography, and each

diastereomeric secondary alcohol could be used in the

synthetic route since at a later stage in the synthesis this

alcohol function was to be oxidized to a methyl ketone.

The stereochemistry at newly created benzylic center

A

more polar, major product 18a (mp 1488C,

[a]²_D⁴2148.1) was reacted with allylbromide and NaH

followed by an air oxidative demetalation to give 19a

([a]²_D¹12.3) in 57% overall yield. Desilylation of 19a

with n-Bu₄NF, bromination with CBr₄and triphenyl-

phosphine in CH₂Cl₂at 08C followed by treatment with

sodium dimethylmalonate gave 20a ([a]²_D⁶113.1) in

45% overall yield which was already converted to (2)-

steganone 5 by previously reported method.^17cSpectral

data of the compound 20a are consistent with that of the

reported compound. A less polar and minor fraction 18b

Scheme 4.

K. Kamikawa et al. / Tetrahedron 56 (2000) 2325±2337

2329

Scheme 5. Reagents and conditions: (a) (i) CH₂CHCH₂Br, NaH, THF, DMF, 63%; (ii) hn-O₂, ether, 90%; (b) (i) hn-O₂, ether; (ii) CH₂CHCH₂Br, NaH,

THF, DMF, 62% from 18b; (c) n-Bu₄NF, THF, 98%; (d) CBr₄, PPh₃, CH₂Cl₂, 08C; (e) NaCH(CO₂Me)₂, MeOH, 45%.

(mp 728C, [a]²_D⁵2139.4) was treated with allylbromide

and NaH to give desired allylated compound in less than

10% yield. The low yield would be contributed to the steric

effect, and therefore, 18b was ®rst exposed to sunlight for

de-tricarbonylchromium followed by treatment with NaH

and allylbromide to give the corresponding 19b

([a]²_D⁵155.8) in 62% yield. Compound 19b was converted

to 20b by the same reaction sequence, and all spectral data

of 20b are consistent with authentic sample (Scheme 5).^17c

rings gave usually various ratios of atropisomeric mixture.

The other method for induction of the axial chirality other

than central bond formation, e.g. enantioselective cleavage

of lactone ring developed by Bringmann et al. is an

attractive procedure for stereoselective synthesis of these

alkaloids.²⁸

As a further extension for the stereoselective axial bond

formation, we next investigated the stereoselective

synthesis of these alkaloids utilizing the planar chiral

(arene)chromium complex.²⁹At ®rst, we have tried the

synthesis of an enantiomerically pure (3,5-dialkoxy-2-

Synthesis of O,O⁰-dimethylkorupenamine A

bromobenzaldehyde)Cr(CO)₃complex as

a coupling

Korupensamines and michellamines have been isolated

from the tropical liana Ancistrocladus korupensis in

Cameroon (Fig. 3), and some of these alkaloids possess

signi®cant pharmacological activities such as antimalarial

properties,²⁴and remarkable antiviral activity against

human immunode®ciency virus strains HIV-1 and

HIV-2.²⁵Structurally, the korupensamines have a naphthyl-

tetrahydroisoquinoline skeleton with an axial chirality

between the naphthalene and tetrahydroisoquinoline rings,

and the michellamines are atropisomerically dimeric

alkaloids of korupensamines. Most biologically active

alkaloid to strains HIV, michellamine B is formed by

dimerization of axially isomeric korupensamine A and B.

These alkaloids have been previously synthesized via the

construction of the axial bond between the naphthalene and

tetrahydroisoquinoline rings as a key step.^26,27However, the

palladium(0)-catalyzed cross-coupling²⁶of two arene rings

or nucleophilic addition²⁷of aryl Grignards to the chiral

o-methoxyaryl oxazoline compounds for the central bond

formation of the naphthalene and tetrahydroisoquinoline

partner. Since tricarbonylchromium complexation of

1-(3⁰,5⁰-dimethoxy-2⁰-bromophenyl)-1,2-propanediol gave

a complexed mixture along with de-brominated compound

as major product, we investigated diastereofacial tricar-

bonylchromium complexation of 1-(3⁰,5⁰-dimethoxy-2⁰-

trimethylsilylphenyl)-1,2-propanediol (Scheme 6). The

threo-diol 21 took place the ligand exchange with naphtha-

lenechromium in THF at 708C to give easily separable dia-

stereomeric mixture in a ratio of 82:18. But, the

corresponding erythro-diol 24 produced a single chromium

complexation product 25 under the same conditions. This

diastereoselective chromium complexation was based on

the con®guration of a benzylic hydroxyl group.³⁰Sarker et

al. reported³¹that potassium hydride reacted with tricarbon-

ylchromium-complexed aryl trimethylsilanes to generate

tricarbonylchromium complexed aryl anions which can be

further trapped with some electrophiles. After protection of

diol, the acetonide complex 26 was treated with potassium

hydride under reported conditions followed by quenching

Figure 3.

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K. Kamikawa et al. / Tetrahedron 56 (2000) 2325±2337

Scheme 6. Tricarbonylchromium complexation by ligand transfer with (naphthalene)Cr(CO)₃.

with various brominating agents. However, only de-silyl-

ation chromium complex was obtained.³²Therefore, the

directed lithiation of 26 was next tried for the introduction

of bromine atom. The complex 26 was reacted with n-BuLi

to give regioselectively bis-trimethylsilyl chromium

complex 27. But, the complex 27 was not further lithiated

at C-6 position due to severe steric hindrance.

.98% ee. Tricarbonylchromium complexation of 29 with

Cr(CO)₆under thermal conditions gave the corresponding

(arene)chromium complex 30 ([a]²_D⁶24.0) in 89% yield.

In order to introduce the bromine atom at either ortho

position of the C-1 side-chain group regioselectively, the

C-4 position was initially protected by an introduction of

an easily removable Me₃Si group. Thus, the lithiation of 30

with n-BuLi followed by treatment with trimethylsilyl-

chloride afforded the trimethylsilylated complex 31

([a]²_D⁷236.0) in 97% yield. Subsequent diastereotopic

lithiation³⁴of 31 followed by quenching with

1,2-dibromo-1,1,2,2-tetra¯uoroethane gave the brominated

complex 32 at the H^a-position without regioisomeric

chromium complex after detrimethylsilylation in 95%

overall yield. This planar chirality of 33 was determined

by X-ray crystallography. In this case, an extremely high

We next turned our attention to diastereoselective ortho

lithiation of the chromium complex having a proper

functional group at C-1 position for the introduction of

bromine as follows (Scheme 7). An asymmetric catalytic

dihydroxylation of (E)-(3,5-dimethoxyphenyl)propene 28

was treated with AD-mix-a,³³and the resulting diol was

subsequently protected with acetone dimethyl acetal to

give the acetonide 29 ([a]²_D⁷123.8) in 96% yield with

Scheme 7.

K. Kamikawa et al. / Tetrahedron 56 (2000) 2325±2337

2331

Scheme 8. Reagents and conditions: (a) 33, Pd(PPh₃)₄, Na₂CO₃, MeOH, H₂O, 708C, 30 min, 90%; (b) hn-O₂, ether, 92%; (c) 1 M aq. HCl, THF, 508C, 96%; (d)

TBDMSCl, imidazole, DMF, 84%; (e) (imd)₂CS. THF; (f) n-Bu₃SnH, AlBN, 62% from 38; (g) n-Bu₄NF, THF, 96%; (h) (PhO)₂PON₃, DEAD, PPh₃, THF; (i)

SnCl₂, MeOH; (j) Ac₂O, py, 66% from 40; (k) POCl₃, MeCN; (l) LiAlH₄. Me₃Al, THF, 278 to 08C, 70% from 44; (m) Pd-black, HCO₂H, MeOH, 458C, 91%.

diastereoselectivity of directed lithiation was achieved even

in THF, while the ortho lithiation of the complex 7 was

largely effected by solvent. Regioselective removal of

diastereotopic H^aproton would be contributed to the coor-

dination of lithium with nearby benzylic oxygen.

SnCl₂followed by acetylation to give the amide compound

44 in 66% overall yield. Bischler±Napieralski cyclization of

44 with POCl₃in acetonitrile gave the naphthyldihydro-

isoquinoline compound 45. Reduction³⁷of the imine double

bond of 45 with LiAlH₄in the presence of Me₃Al afforded

trans-dimethyl compound 46 along with small amount of

the corresponding cis-isomer (ratio; 93:7) in 70% overall

yield. Finally, debenzylation with Pd-black in a solution

of 8.8% formic acid in MeOH gave O,O⁰-dimethylkorupens-

amine A 47 (RH) in 91% yield.

The planar chiral bromobenzene complex 33 was easily

converted to O,O⁰-dimethylkorupensamine A as follows

(Scheme 8). Palladium(0)-catalyzed cross-coupling of the

planar chiral (arene)Cr(CO)₃complex 33 with 4-benzyl-

oxy-5-methoxy-6-methylnaphthylboronic acid 34^26fin the

presence of sodium carbonate in aqueous MeOH at re¯ux

for 30 min produced a single atropisomeric coupling

product 35 in 90% yield without any formation of the

atropisomers. The axial stereochemistry of the coupling

In conclusion, we have demonstrated the asymmetric

synthesis of axially chiral biaryl natural products by stereo-

selective Pd(0)-mediated cross-coupling method by using

planar chiral arene chromium complexes.

1

product 35 was assigned to be the (S)-con®guration by H

NMR spectra, in which the peri-proton of naphthalene ring

appeared at a lower ®eld (8.62 ppm) due to the anisotropic

effect of the syn-Cr(CO)₃fragment.²³An oxidative demeta-

lation of 35 and subsequent treatment with dilute HCl

afforded the dihydroxyl compound 37. Selective protection

of the hydroxyl at the homobenzylic position of 37 with tert-

butyldimethylsilyl chloride gave the mono-silylated

compound 38 ([a]²_D⁵135.8) in 84% yield. The benzylic

hydroxyl of 38 was removed by Barton method³⁵to give the

deoxygenation compound 40 in 62% yield. The substitution

of the hydroxyl to nitrogen atom with the stereochemical

inversion was achieved under Mitsunobu conditions.³⁶

Thus, deprotection of the silyl ether 40 and subsequent treat-

ment with (PhO)₂PON₃in the presence of DEAD and PPh₃

produced the azide compound 42 which was reduced with

Experimental

All manipulations involving organometallics were carried

out under an atmosphere of nitrogen or argon and using an

inert gas/vacuum double manifold techniques. All melting

points were determined on a Yanagimoto MPJ-2 micro-

1

melting point apparatus and were uncorrected. H NMR

spectra were measured on Hitachi R-90, JEOL GX-400,

EX-270 instrument, and all NMR spectra were recorded in

CDCl₃solvent with tetramethylsilane as an internal

reference. IR spectra were determined in CHCl₃solution

on a JASCO A-100 spectrometer. Elemental analyses

were performed on a Perkin±Elmer Model 240 automatic

analyzer. Mass spectra were determined on a JEOL

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K. Kamikawa et al. / Tetrahedron 56 (2000) 2325±2337

JMS-AM 500 with EI mode (70 eV). Optical rotations were

obtained on a JASCO DIP-370 automatic polarimeter at

wavelength 589 nm (sodium D line) using a 1.0-dm cell

with a total volume of 3 mL. Diethyl ether and tetrahydro-

furan were distilled from sodium/benzophenone ketyl

immediately before use.

2-propanol in hexane; ¯ow rate 1.0 mL/min; column

temperature 408C; UV detector 254 nm; retention time:

12.4 min for 9 and 19.0 min for enantiomer. mp 1138C;

[a]¹_D⁹11036 (c1.18, CHCl₃); ¹H NMR (400 MHz,

CDCl₃) d 3.78 (3H, s), 3.98 (3H, s), 4.03 (3H, s), 5.64

(1H, s), 9.99 (1H, s); IR (CHCl₃) 1980, 1910, 1680, 1300,

1000 cm²¹; Anal. calcd for C₁₃H₁₁O₇CrBr: C, 37.98; H,

2.70. Found: C, 38.08; H, 2.64.

Preparation of chromium complex 7. A mixture of

2-(3⁰,4⁰,5⁰-trimethoxyphenyl)-4-methoxymethyl-1,3-dioxane

6 (3.62 g, 12.2 mmol) and chromium hexacarbonyl (2.94 g,

13.8 mmol) in di-n-butyl ether (300 mL) and THF (30 mL)

was heated at 1408C for 18 h under nitrogen. After evapo-

ration of the solvent under reduced pressure, the residue was

diluted with dichloromethane, ®ltered through Celite, and

concentrated in vacuo. The crude, yellow solid was

recrystallized from ether/hexane to give the (arene)chro-

mium complex 7 (3.27 g, 62%) as yellow crystals. mp

1038C (dec); [a]_D²⁷219.6 (c1.88, CHCl₃); ¹H NMR

(400 MHz, CDCl₃) d 1.55 (1H, brd, J12.2 Hz), 1.89 (1H,

dq, J4.9, 12.2 Hz), 3.42 (3H, s), 3.47 (1H, dd, J4.3,

10.4 Hz), 3.55 (1H, dd, J6.1, 10.4 Hz), 3.85 (6H, s), 3.88

(3H, s), 3.97 (1H, dt, J1.8, 12.2 Hz), 4.04±4.12 (1H, m),

4.31 (1H, dd, J4.9, 12.2 Hz), 4.31 (1H, dd, J4.9,

12.2 Hz), 4.97 (1H, s), 5.06 (1H, s), 5.37 (1H, s); IR

(CHCl₃) 1970, 1890, 1240, 1160, 1130 cm²¹; Anal. calcd

for C₁₈H₂₂O₉Cr: C, 49.77; H, 5.10. Found: C, 49.85; H, 5.15.

Reduction of complex 9 to give 12. A solution of (benzal-

dehyde)chromium complex 9 (2.00 g, 4.87 mmol) in MeOH

(80 mL) was added to a solution of sodium borohydride

(0.370 g, 9.74 mmol) in MeOH (20 mL) under argon. The

reaction mixture was stirred for 5 min and quenched with

H₂O. The solvent was evaporated under reduced pressure.

The residue was extracted with ether, and the extract was

washed with brine, dried over anhydrous MgSO₄, and

evaporated under reduced pressure. The residue was puri-

®ed by silica gel chromatography (35% ether in hexane) to

give (benzylalcohol)chromium complex 12 (1.97 g, 98%) as

yellow crystals. mp 1308C (dec); [a]²_D⁴2214 (c1.42,

CHCl₃); ¹H NMR (400 MHz, CDCl₃) d 2.26 (1H, bd,

J6.1 Hz), 3.81 (3H, s), 3.95 (3H, s), 4.00 (3H, s), 4.69

(1H, dd, J6.1, 14.0 Hz), 4.75 (1H, dd, J6.1, 14.0 Hz),

5.24 (1H, s); IR (CHCl₃) 3600, 1960, 1880, 1310, 1020,

1000 cm²¹; Anal. calcd for C₁₃H₁₃O₇CrBr: C, 37.79; H,

3.17. Found: C, 37.85; H, 3.11.

Directed lithiation of 7. To a solution of (arene)chromium

complex 7 (2.00 g, 4.60 mmol) in dry toluene (160 mL) was

added n-BuLi (1.6 M in hexane, 7.20 mL, 11.5 mmol) at

2788C under argon. After stirring for 1 h at 2788C, 1,2-

dibromo-1,1,2,2-tetra¯uoroethane (1.60 mL, 13.8 mmol)

was added at 2788C. The reaction mixture was warmed to

2308C, quenched with saturated aqueous NH₄Cl at 08C, and

extracted with ether. The extract was washed with brine,

dried over anhydrous MgSO₄, and evaporated under

reduced pressure. The residue was puri®ed by silica gel

chromatography with hexane/ether to give (bromobenzene)-

chromium complex 8 (1.28 g, 54%) as yellow crystals along

with recovery of starting material (0.78 g): recrystallization

from ether/hexane. mp 82±848C; [a]²_D⁷2128.0 (c1.65,

CHCl₃); ¹H NMR (400 MHz, CDCl₃) d 1.55 (1H, bd,

J12.2 Hz), 1.95 (1H, dq, J4.9, 12.2 Hz), 3.39 (3H, s),

3.47 (1H, dd, J4.3, 10.4 Hz), 3.51 (1H, dd, J5.5,

10.4 Hz), 3.80 (3H, s), 3.93 (3H, s), 3.97 (3H, s), 4.06

(1H, dt, J2.4, 12.2 Hz), 4.08±4.14 (1H, m), 4.37 (1H,

dd, J4.9, 12.2 Hz), 5.34 (1H, s), 5.55 (1H, s); IR

(CHCl₃) 1960, 1880, 1100, 1000 cm²¹; Anal. calcd for

C₁₈H₂₁O₉CrBr: C, 42.12; H, 4.12. Found: C, 42.14; H, 4.06.

Palladium(0)-mediated cross-coupling of 12 to give 14. A

mixture of planar chiral (bromobenzylalcohol)chromium

complex 12 (1.00 g, 2.42 mmol), phenylboronic acid 13

(0.940 g, 4.84 mmol), and Pd(PPh₃)₄(140 mg, 0.12 mmol)

in aqueous 1.0 M Na₂CO₃(4 mL) and MeOH (40 mL) was

degassed and re¯uxed for 1 h under argon. The solvent was

evaporated in vacuo. The residue was extracted with ether.

The extract was washed with aqueous 1 M NaOH and brine,

dried over anhydrous MgSO₄, and evaporated under

reduced pressure. The residue was puri®ed by silica gel

chromatography with ether/hexane to give the cross-

coupling product 14 (787 mg, 67%) as yellow crystals. mp

140±1428C; [a]²_D⁵2161.5 (c2.13, CHCl₃); ¹H NMR

(400 MHz, CDCl₃) d 1.86 (1H, bs), 3.72 (3H, s), 3.91

(3H, s), 3.94 (3H, s), 4.20 (2H, d, J6.1 Hz), 5.13 (1H, s),

6.15 (2H, s), 7.00 (1H, s), 7.35 (1H, s), 9.74 (1H, s); IR

(CHCl₃) 3600, 1960, 1880, 1310, 1020, 1000 cm²¹; Anal.

calcd for C₂₁H₁₈O₁₀Cr: C, 52.29; H, 3.76. Found: C, 51.99;

H, 3.86.

Protection of 14 with chloro t-butyldimethylsilane. To a

solution of coupling product 14 (70 mg, 0.15 mmol) and

imidazole (30 mg, 0.44 mmol) in dry CH₂Cl₂was added a

solution of chloro t-butyldimethylsilane (44 mg,

0.29 mmol) in dry CH₂Cl₂(1 mL). The reaction mixture

was stirred at 258C for 2 h, and extracted with CH₂Cl₂.

The extract was washed with brine, dried over anhydrous

MgSO₄, and evaporated under reduced pressure. The

residue was puri®ed by silica gel chromatography to give

silyl ether (76 mg, 87%) as yellow crystals. mp 1578C (dec);

[a]²_D¹2184.8 (c0.353, CHCl₃); ¹H NMR (400 MHz,

CDCl₃) d 20.05 (3H, s), 0.00 (3H, s), 0.86 (9H, s), 3.72

(3H, s), 3.89 (3H, s), 3.93 (3H, s), 4.13 (1H, d, J12.8 Hz),

4.15 (1H, d, J12.8 Hz), 5.10 (1H, s), 6.15 (2H, s), 6.99

(1H, s), 7.38 (1H, s), 9.72 (1H, s); IR (CHCl₃) 1950, 1880,

(1S, 2R)-Tricarbonyl(2-bromo-3,4,5-trimethoxybenzalde-

hyde)chromium 9. A solution of chromium complex 8

(100 mg, 0.195 mmol) in aqueous 6 M HCl (5 mL) and

THF (5 mL) was degassed by three freeze/vacuum/thaw

cycles and warmed to 408C for 30 min under argon. After

cooling to room temperature, the reaction mixture was

extracted with ether. The extract was washed with saturated

aqueous NaHCO₃and brine, dried over anhydrous MgSO₄,

and evaporated under reduced pressure. The residue was

puri®ed by silica gel chromatography with ether/hexane to

give (benzaldehyde)chromium complex 9 (66 mg, 83%,

.99% ee) as red crystals. An enantiomeric purity was

determined by HPLC with Chiralcel OJ eluted with 10%

K. Kamikawa et al. / Tetrahedron 56 (2000) 2325±2337

2333

1680, 1260, 1240, 1200, 1100 cm²¹; Anal. calcd for

C₂₇H₃₂O₁₀CrSi: C, 54.35; H, 5.41. Found: C, 54.38; H, 5.37.

3.75±3.81 (1H, m), 3.88 (3H, s), 3.85±3.91 (1H, m), 3.91

(3H, s), 4.13 (1H, d, J13.6 Hz), 4.14 (1H, q, J6.1 Hz),

4.36 (1H, d, J13.6 Hz), 5.07 (1H, dd, J1.8, 10.4 Hz),

5.23 (1H, dd, J1.8, 17.1 Hz), 5.82±5.92 (1H, m), 6.00

(1H, s), 6.51 (1H, s), 6.98 (1H, s), 7.09 (1H, s); IR

(CHCl₃) 1220, 1140, 1100, 930, 910 cm²¹; MS (relative

intensity) m/z 516 (M¹, 3), 458 (72), 401 (10), 386 (100);

HRMS calcd for C₂₈H₄₀O₇Si 516.2543, found 516.2533.

MeLi addition to give complex 18a and 18b. To a solution

of silyl ether complex (366 mg, 0.613 mmol) in dry ether

(30 mL) was added MeLi (0.77 mL, 1.06 M in ether,

1.23 mmol) at 2788C under argon, and warmed to

2508C. The reaction mixture was quenched with saturated

aqueous NH₄Cl, and extracted with ether. The extract was

washed with brine, dried over anhydrous MgSO₄, and

evaporated under reduced pressure. The residue was puri-

®ed by silica gel chromatography to give alcohol 18a

(298 mg, 79%) and diastereomeric isomer 18b (85 mg,

15%) as yellow crystals, respectively. First fraction 18b.

Preparation of 20a. To a solution of demetalated

compound 19a (165 mg, 0.321 mmol) in THF (15 mL)

was added n-Bu₄NF (0.6 mL, 1.0 M in THF, 0.6 mmol) at

08C. The reaction mixture was stirred for 3 h at 08C,

quenched with buffer solution and extracted with ether.

The extract was washed with brine, dried over anhydrous

MgSO₄, and evaporated under reduced pressure. The

residue was puri®ed by silica gel chromatography to give

benzyl alcohol (125 mg, 0.311 mmol, 97%). To a solution

of alcohol (125 mg, 0.311 mmol) and CBr₄(129 mg,

0.389 mmol) in dry CH₂Cl₂was added triphenylphosphine

(122 mg, 0.467 mmol) at 08C under argon. The reaction

mixture was stirred for 5 min, and evaporated under reduced

pressure. The residue was dissolved with ether. The precipi-

tate was ®ltered off, and the solution was concentrated under

reduced pressure. The residue was puri®ed by silica gel

chromatography to give a benzyl bromide. A solution of

this benzyl bromide in dry MeOH (2 mL) was added to a

solution of dimethyl sodiomalonate, prepared from

dimethyl malonate (148 mg, 1.12 mmol) and sodium

(79 mg, 3.42 mmol) in dry MeOH (2 mL), at 258C under

argon. The reaction mixture was stirred for 1 h, and was

quenched with diluted aqueous HCl, and extracted with

ether. Usual workup gave 20a (57 mg, 36%) as colorless

oil. [a]²_D⁶113.1 (c1.40, THF) lit.16c; [a]_D18.8

1

mp 71±738C; [a]²_D⁵2139.4 (c1.54, CHCl₃); H NMR

(400 MHz, CDCl₃) d 0.06 (6H, s), 0.85 (9H, s), 1.37 (3H,

d, J6.1 Hz), 2.87 (1H, bs), 3.78 (3H, s), 3.88 (3H, s), 3.93

(3H, s), 4.13 (1H, d, J11.6 Hz), 4.19 (1H, d, J11.6 Hz),

4.58 (1H, q, J6.1 Hz), 4.92 (1H, s), 6.02 (1H, s), 6.03 (1H,

s), 6.83 (1H, s), 7.04 (1H, s); IR (CHCl₃) 3500±3100, 1950,

1870, 1240, 1140, 1100, 1080, 1040 cm²¹; Anal. calcd for

C₂₈H₃₂O₁₆CrSi: C, 54.89; H, 5.92. Found: C, 54.97; H, 5.89.

Second fraction 18a; mp 147±1498C; [a]²_D⁰2148.1

(c1.42, CHCl₃); ¹H NMR (400 MHz, CDCl₃) d 0.00

(3H, s), 0.05 (3H, s), 0.90 (9H, s), 1.33 (3H, d, J6.1 Hz),

2.17 (1H, bs), 3.87 (6H, s), 3.92 (3H, s), 4.02 (1H, d,

J13.4 Hz), 4.27 (1H, d, J13.4 Hz), 4.58 (1H, q,

J6.1 Hz), 5.22 (1H, s), 6.03 (1H, s), 6.04 (1H, s), 6.84

(1H, s), 7.04 (1H, s); IR (CHCl₃) 3500±3100, 1950, 1870,

1240, 1140, 1100, 1080, 1040 cm²¹; Anal. calcd for

C₂₈H₃₂O₁₆CrSi: C, 54.89; H, 5.92. Found: C, 55.05; H, 5.90.

Preparation of 19a. A solution of alcohol 18a (224 mg,

0.367 mmol) in dry THF (5 mL) was added to a suspension

of NaH (40 mg, 60% in oil, 0.55 mmol) in dry THF (5 mL)

and DMF (2 mL) at 258C under argon. The reaction mixture

was stirred for 30 min, and then allyl bromide (0.073 mL,

0.84 mmol) was added. The mixture was stirred for 1 h,

quenched with buffer solution (0.025 M aqueous KH₂PO₄,

0.025 M aqueous Na₂HPO₄), and extracted with ether. The

extract was washed with brine, dried over anhydrous

MgSO₄, and evaporated under reduced pressure. The

residue was puri®ed by silica gel chromatography to give

allyl ether complex (150 mg, 63%) as yellow oil.

[a]²_D⁰2165.4 (c1.03, CHCl₃); ¹H NMR (400 MHz,

CDCl₃) d 0.01 (3H, s), 0.07 (3H, s), 0.91 (9H, s), 1.20

(3H, d, J6.1 Hz), 3.73±3.84 (2H, m), 3.87 (3H, s), 3.88

(3H, s), 3.92 (3H, s), 4.09 (1H, d, J13.4 Hz), 4.21 (1H, q,

J6.1 Hz), 4.38 (1H, d, J13.4 Hz), 5.12 (1H, dd, J10.4,

1.5 Hz), 5.23 (1H, dd, J18.9, 1.5 Hz), 5.27 (1H, s), 5.81±

5.91 (1H, m), 6.03 (1H, s), 6.04 (1H, s), 6.81 (1H, s), 7.05

1

(c1.40, THF); H NMR (400 MHz, CDCl₃) d 1.20 (3H,

d, J6.1 Hz), 2.78 (1H, dd, J14.7, 6.1 Hz), 2.93 (1H, dd,

J9.2, 14.7 Hz), 3.55±3.82 (3H, m), 3.62 (3H, m), 3.67

(3H, s), 3.68 (3H, s), 3.86 (6H, s), 4.06 (1H, q, J6.1 Hz),

5.06 (1H, dd, J1.2, 10.4 Hz), 5.20 (1H, dd, J1.2,

17.1 Hz), 5.79±5.89 (1H, m), 6.00 (1H, d, J1.2 Hz),

6.01 (1H, d, J1.2 Hz), 6.54 (1H, s), 6.55 (1H, s), 7.09

(1H, s); IR (CHCl₃) 1750, 1730, 1230 cm²¹; MS (relative

intensity) m/z 516 (M¹, 26), 458 (100), 427 (20), 327 (57);

HRMS calcd for C₂₇H₃₂O₁₀516.1996, found 516.2025.

Complexation of erythro-diol 24 with (naphthalene)-

Cr(CO)₃. A mixture of erythro-diol 24 (568 mg, 2.00

mmol) and (naphthalene)Cr(CO)₃(581 mg, 2.20 mmol) in

THF (20 mL) in sealed tube was degassed by three freeze/

vacuum/thaw cycles and heated at 708C for 3.0 h under

argon. The precipitate was ®ltered off and the solution

was evaporated under reduced pressure. The residue was

puri®ed by silica gel chromatography to give chromium

complex 25 (547 mg, 65%) as yellow crystals. mp 127±

(1H, s); IR (CHCl₃) 1950, 1870, 1240, 1140, 940, 910 cm²¹

;

MS (relative intensity) m/z 652 (M¹, 14), 568 (13), 527

(100), 458 (66); HRMS calcd for C₃₁H₄₀O₁₀CrSi

652.1796; found 652.1781. A solution of the allyl ether

chromium complex (57 mg, 0.087 mmol) in ether (20 mL)

was exposed to sunlight until the yellow solution became

colorless. The precipitate was ®ltered off, and the solution

was evaporated under reduced pressure and puri®ed by

silica gel chromatography to give demetalated compound

19a (42 mg, 94%) as colorless oil. [a]²_D⁵12.3 (c1.18,

1

1318C (dec); H NMR (270 MHz, CDCl₃) d 0.37 (9H, s),

1.20 (3H, d, J6.4 Hz), 2.04 (1H, bd, J5.3 Hz), 2.43 (1H,

bd, J3.7 Hz), 3.77 (3H, s), 3.80 (3H, s), 3.77±3.90 (1H,

m), 4.95 (1H, t, J3.7 Hz), 5.14 (1H, d, J1.8 Hz), 5.21

(1H, d, J1.8 Hz); ¹³C NMR (67.5 MHz, CDCl₃) d 2.6,

16.6, 55.5, 55.7, 66.0, 70.9, 72.0, 72.7, 83.0, 119.2, 144.0,

148.0, 234.3; IR (CHCl₃) 3600, 3000, 2400, 1950, 1860,

1530, 1210 cm²¹; Anal. calcd for C₁₇H₂₄O₇CrSi: C, 48.56;

H, 5.75, Found: C, 48.46; H, 5.70.

1

CHCl₃); H NMR (400 MHz, CDCl₃) d 0.00 (3H, s), 0.03

(3H, s), 0.91 (9H, s), 1.13 (3H, d, J6.1 Hz), 3.59 (3H, s),

2334

K. Kamikawa et al. / Tetrahedron 56 (2000) 2325±2337

Preparation of acetonide 29. To a stirred mixture of AD-

mix-a (9.8 g, 1.4 g/mmol) and methane sulfonamide

(0.667 g, 7.00 mmol) in t-BuOH (35 mL) and water

(35 mL) was added (E)-1-(3,5-dimethoxyphenyl)-1-

propene (28) (1.25 g, 7.00 mmol) at 258C. The reaction

mixture was stirred vigorously at 258C for 2.0 h. Sodium

thiosulfate (10 g) was added, and the mixture was stirred at

258C for 30 min. The reaction mixture was extracted with

EtOAc, washed with aqueous 2 M KOH (35 mL) and brine

(35 mL). The extract was dried over anhydrous MgSO₄, and

evaporated under reduced pressure. The crude product was

puri®ed by silica gel chromatography to afford (1S,2S)-1-

(3,5-dimethoxyphenyl)-1,2-propanediol (1.48 g, 99%, 98%

ee) as colorless oil. [a]²_D⁷116.8 (c1.06, EtOH); ¹H NMR

(270 MHz, CDCl₃) d 1.07 (3H, d, J6.9 Hz), 2.56 (1H, brs),

2.76 (1H, brs), 3.78 (6H, s), 3.83 (1H, q, J6.9 Hz), 4.27

(1H, d, J6.9 Hz), 6.39 (1H, t, J2.3 Hz), 6.49 (2H, d,

J2.3 Hz); IR (CHCl₃) 3325, 2950, 1600, 1300, 1160,

1040 cm²¹; MS (relative intensity) m/z 212 (M¹, 76), 168

(100), 167 (86), 139 (97), 124 (44); HRMS calcd for

C₁₁H₁₆O₄212.1003, found 212.1026. Anal. Calcd for

C₁₁H₁₆O₄: C, 62.25; H, 7.60. Found: C, 62.25; H, 7.68. A

mixture of diol (1.43 g, 6.74 mmol) and catalytic amount of

p-toluenesulfonic acid monohydrate in 2,2-dimethoxypro-

pane (20 mL) was stirred at 258C for 30 min. Usual workup

gave acetonide 29 (1.65 g, 97%) as colorless oil.

[a]²_D⁷123.8 (c1.12, CHCl₃); ¹H NMR (270 MHz,

CDCl₃) d 1.31 (3H, d, J5.9 Hz), 1.51 (3H, s), 1.55 (3H,

s), 3.80 (6H, s), 3.85 (1H, dq, J5.9, 8.6 Hz), 4.41 (1H, d,

J8.6 Hz), 6.41 (1H, t, J2.3 Hz), 6.54 (2H, d, J2.3 Hz);

¹³C NMR (67.5 MHz, CDCl₃) d 16.4, 26.8, 27.4, 55.3, 79.0,

89.7, 99.8, 104.3, 108.5, 140.3, 160.9; IR (CHCl₃) 2950,

1880 cm²¹; Anal. calcd for C₂₀H₂₈O₇CrSi: C, 52.16; H,

6.13. Found: C, 52.21; H, 6.19.

Lithiation of 31 to give brominated complex 32. To a

solution of complex 31 (1.50 g, 3.26 mmol) and TMEDA

(0.74 mL, 4.89 mmol) in dry THF (33 mL) was added

n-BuLi (3.06 mL, 1.6 M in hexane, 4.89 mmol) at 2788C

under argon atmosphere. The reaction mixture was stirred

for 1.0 h at 2788C followed by addition of 1,2-dibromo-

1,1,2,2-tetra¯uoroethane (0.78 mL, 6.52 mmol). After the

addition, the reaction mixture was warmed to 258C,

quenched with saturated aqueous NH₄Cl at 08C, and

extracted with EtOAc. Usual puri®cation gave 32 (1.73 g,

98%) as yellow crystals. mp 138±1408C; [a]²_D⁷235.6

(c1.00, CHCl₃); ¹H NMR (270 MHz, CDCl₃) d 0.42

(9H, s), 1.49 (3H, s), 1.55 (3H, s), 1.61 (3H, d, J6.3 Hz),

3.71 (3H, s), 3.82 (3H, s), 3.87 (1H, dq, J4.6, 6.3 Hz), 5.02

(1H, s), 5.16 (1H, d, J4.9 Hz); ¹³C NMR (67.5 MHz,

CDCl₃) d 1.5, 20.3, 28.3, 28.7, 55.8, 63.0, 70.7, 76.6,

82.7, 83.9, 87.9, 107.2, 110.8, 144.5, 145.0, 232.2; IR

(CHCl₃) 1970, 1895 cm²¹; Anal. calcd for C₂₀H₂₇O₇BrCrSi:

C, 44.53; H, 5.04. Found: C, 44.51; H, 5.02.

Cross-coupling of 33 to give 35. Cross-coupling was

carried out under above conditions. Yield 90%.

[a]²_D⁸2142.9 (c1.11, CHCl₃); ¹H NMR (270 MHz,

CDCl₃) d 1.08 (3H, d, J5.9 Hz), 1.21 (3H, s), 1.31 (3H,

s), 2.55 (3H, s), 3.64 (3H, s), 3.85 (3H, s), 3.96 (3H, s), 4.26

(1H, d, J5.9 Hz), 4.37 (1H, qui, J5.9 Hz), 5.23 (2H, s),

5.24 (1H, d, J2.3 Hz,), 5.30 (1H, d, J2.3 Hz), 6.76 (1H,

s), 6.84 (1H, d, J7.9 Hz), 7.17 (1H, d, J7.9 Hz), 7.33

(1H, t, J7.3 Hz), 7.42 (2H, t, J7.3 Hz), 7.62 (2H, d,

J7.3 Hz), 8.62 (1H, s); ¹³C NMR (67.5 MHz, CDCl₃) d

20.2, 21.7, 27.8, 28.1, 55.8, 56.1, 56.3, 65.7, 71.0, 72.1,

77.9, 81.3, 98.8, 106.0, 108.8, 110.2, 112.0, 116.0, 118.4,

119.6, 126.9, 127.5, 128.3, 132.0, 135.0, 136.5, 137.5,

141.2, 142.7, 156.8, 157.2, 233.3; IR (CHCl₃) 1960, 1870,

1580 cm²¹; MS (relative intensity) m/z 664 (M¹, 11), 618

(17), 580 (61), 565 (32), 544 (100); HRMS calcd for

C₃₆H₃₆O₉Cr 664.1728, found 664.1746; Anal. calcd for

C₃₆H₃₆O₉Cr: C, 65.06; H, 5.46. Found: C, 64.74; H, 5.67.

1600, 1160 cm²¹

; MS (relative intensity) m/z 252

(M¹, 66), 237 (26), 208 (100), 193 (99) 177 (36) 149

(39). HRMS calcd for C₁₄H₂₀O₄252.1398, found

252.1369.

Preparation of chromium complex 30. Chromium

complexation with Cr(CO)₆was carried out under above

method. Yield 89%; mp 150±1528C; [a]²_D⁶24.0

(c1.01, CHCl₃); ¹H NMR (270 MHz, CDCl₃) d 1.41

(3H, d, J6.3 Hz), 1.51 (3H, s), 1.52 (3H, s), 3.75 (3H, s),

3.76 (3H, s), 3.89 (1H, dq, J6.3, 8.2 Hz), 4.27 (1H, d,

J8.2 Hz), 4.69 (1H, bs), 5.09 (1H, bs), 5.14 (1H, t,

J2.0 Hz); ¹³C NMR (67.5 MHz, CDCl₃) d 17.0, 26.6,

27.3, 55.8, 67.9, 69.5, 71.1, 78.9, 82.2, 108.8, 109.3,

143.3, 143.4, 233.1; IR (CHCl₃) 1960, 1880, 1540,

1160 cm²¹; Anal. calcd for C₁₇H₂₀O₇Cr: C, 52.58; H,

5.19. Found: C, 52.44; H, 5.15.

Preparation of axial biaryl compound 37. A solution of 35

(1.33 g, 2.00 mmol) in ether (40 mL) was exposed to

sunlight to give biaryl 36 (973 mg, 92%) as colorless

foam. [a]²_D⁶239.3 (c1.00, CHCl₃); ¹H NMR

(270 MHz, CDCl₃) d 0.54 (3H, d, J5.9 Hz), 1.25 (3H,

s), 1.51 (3H, s), 2.32 (3H, s), 3.60 (3H, s), 3.91 (3H, s),

3.91 (1H, m), 3.95 (3H, s), 4.23 (1H, d, J8.3 Hz), 5.25

(2H, s), 6.55 (1H, d, J2.3 Hz), 6.65 (1H, s), 6.66 (1H, s),

6.82 (1H, d, J2.3 Hz), 6.94 (1H, d, J7.9 Hz), 7.20 (1H, d,

J7.9 Hz), 7.32 (1H, t, J7.3 Hz), 7.42 (2H, t, J7.3 Hz),

7.64 (2H, d, J7.3 Hz); IR (CHCl₃) 2860, 1580, 1460, 1380,

1160, 1080 cm²¹; Anal. calcd for C₃₃H₃₆O₆: C, 74.98; H,

6.86. Found: C, 74.87; H, 6.90. A solution of 36 (200 mg,

0.379 mmol) in THF (4 mL) and aqueous 1 M HCl (1 mL)

was stirred at 508C for 15 h. Usual workup gave diol 37

(1.77 mg, 96%) as pale yellow foam. [a]²_D⁷13.5

(c1.10, CHCl₃); ¹H NMR (270 MHz, CDCl₃) d 0.70

(3H, d, J6.6 Hz), 1.70 (1H, bs), 2.20 (1H, bs), 2.31 (3H,

d), 3.60 (3H, s), 3.80 (1H, qui, J6.6 Hz), 3.90 (3H, s), 3.94

(3H, s), 4.08 (1H, d, J6.6 Hz), 5.22 (2H, d), 6.54 (1H, d,

J2.3 Hz), 6.65 (1H, s), 6.67 (1H, s), 6.70 (1H, d,

Preparation of complex 31. To a solution of complex 30

(1.36 g, 3.50 mmol) and TMEDA (0.58 mL, 3.85 mmol) in

dry THF (35 mL) was added n-BuLi (2.41 mL, 1.6 M in

hexane, 3.85 mmol) at 2788C under argon atmosphere.

The reaction mixture was stirred for 1.0 h at 2788C

followed by addition of chlorotrimethylsilane (0.67 mL,

5.25 mmol), and usual workup afforded silylated chromium

complex 31 (1.56 g, 97%) as yellow crystals. mp 159±

1618C; [a]²_D⁷236.0 (c1.07, CHCl₃); ¹H NMR

(270 MHz, CDCl₃)

d 0.33 (9H, s), 1.43 (3H, d,

J5.9 Hz), 1.52 (3H, s), 1.53 (3H, s), 3.69 (3H, s), 3.71

(3H, s), 3.93 (1H, dq, J5.9, 8.2 Hz), 4.35 (1H, d,

J8.2 Hz), 4.52 (1H, s), 4.97 (1H, s); IR (CHCl₃) 1960,

K. Kamikawa et al. / Tetrahedron 56 (2000) 2325±2337

2335

J2.3 Hz), 6.90 (1H, d, J7.9 Hz), 7.15 (1H, d, J7.9 Hz),

7.33 (1H, t, J7.3 Hz), 7.42 (2H, t, J7.3 Hz), 7.63 (2H, d,

MS (relative intensity) m/z 488 (M¹, 52), 470 (41), 442 (81),

379 (50), 351 (100); HRMS, calcd for C₃₀H₃₂O₆488.2209,

found 488.2204.

foam. [a]²_D⁵118.4 (c1.00, CHCl₃); ¹H NMR

(270 MHz, CDCl₃) d 0.83 (3H, d, J5.9 Hz), 2.28 (1H,

dd, J8.3, 13.5 Hz), 2.32 (3H, s), 2.50 (1H, dd, J13.5,

4.6 Hz), 3.60 (3H, s), 3.60±3.70 (1H, m), 3.89 (3H, s),

3.94 (3H, s), 5.23 (2H, s), 6.50 (1H, d, J2.3 Hz), 6.55

(1H, d, J2.3 Hz), 6.67 (1H, s), 6.68 (1H, s), 6.92 (1H, d,

J7.9 Hz), 7.13 (1H, d, J7.9 Hz), 7.32 (1H, t, J7.3 Hz),

7.42 (2H, t, J7.3 Hz), 7.63 (2H, d, J7.3 Hz); IR (CHCl₃)

3300, 2950 1580, 1370, 1320, 1160, 1080 cm²¹; MS

(relative intensity) m/z 472 (M¹, 61), 454 (50), 381 (18),

363 (100), 335 (32); HRMS calcd for C₃₀H₃₂O₅472.2262,

found 472.2256.

J7.3 Hz); IR (CHCl₃) 3300, 1580, 1390, 1330, 1180 cm²¹

;

Preparation of 40. A solution of diol 37 (852 mg,

1.74 mmol), t-butylchlorodimethylsilane (316 mg, 2.09

mmol) and imidazole (238 mg, 3.49 mmol) in dry DMF

(3.5 mL) was stirred at 258C for 3 h under argon. Usual

workup gave silylated compound 38 (888 mg, 84%) as

1

colorless foam. [a]_D²⁵135.8 (c1.11, CHCl₃); H NMR

(270 MHz, CDCl₃) d 20.14 (6H, s), 0.53 (3H, d,

J6.0 Hz), 0.82 (9H, s), 2.32 (3H, s), 3.06 (1H, d,

J6.0 Hz), 3.54 (1H, dq, J4.3, 6.0 Hz), 3.61 (3H, s),

3.91 (3H, s), 3.96 (3H, s), 4.27 (1H, dd, J4.3, 6.0 Hz),

5.24 (2H, s), 6.52 (1H, d, J2.3 Hz), 6.67 (1H, s), 6.72

(1H, s), 6.73 (1H, d, J2.3 Hz), 7.07 (1H, d, J7.9 Hz),

7.24 (1H, d, J7.9 Hz), 7.33 (1H, t, J7.3 Hz), 7.42 (2H,

t, J7.3 Hz), 7.64 (2H, d, J7.3 Hz); IR (CHCl₃) 3300,

2950, 1580, 1460, 1380, 1320, 1180, 840 cm²¹; MS

(relative intensity) m/z 602 (M¹, 100), 584 (13), 557 (8),

493 (13), 470 (30); HRMS calcd for C₃₆H₄₆O₆Si 602.3120,

found 602.3092. A solution of silylated compound 38

(888 mg, 1.48 mmol) and 1,1⁰-(thiocarbonyl)diimidazole

(656 mg, 3.68 mmol) in THF (3 mL) was stirred at 258C

under argon. After 24 h, the reaction mixture was concen-

trated under reduced pressure, and the residue was puri®ed

to give the crude pale yellow foam of 39 (813 mg). ¹H NMR

(270 MHz, CDCl₃) d 20.30 (3H, s), 20.16 (3H), 0.79 (9H,

s), 0.86 (3H, d, J6.0 Hz), 2.26 (3H, s), 3.60 (3H, s), 3.72

(1H, dq, J3.6, 6.3 Hz), 3.85 (3H, s), 3.97 (3H, s), 5.27 (2H,

s), 6.09 (1H, d, J3.6 Hz), 6.56 (1H, d, J2.3 Hz), 6.63

(1H, s), 6.63 (1H, d, J2.3 Hz), 6.64 (1H, s), 6.98 (2H,

m), 7.33 (1H, t, J7.3 Hz), 7.41±7.46 (4H, m), 7.65 (2H,

d, J7.3 Hz), 8.21 (1H, s); ¹³C NMR (67.5 MHz, CDCl₃) d

24.9, 24.8, 17.8, 21.2, 22.1, 25.6, 55.4, 56.0, 56.2, 69.7,

71.2, 87.3, 98.4, 105.3, 107.0, 108.4, 116.3, 117.7, 117.8,

121.2, 125.5, 127.0, 127.5, 128.4, 130.6, 136.1, 136.7,

137.1, 137.7, 137.8, 156.0, 157.3, 159.0, 159.9, 183.4,

217.3. To a solution of the crude thioimidazolide and

trace amount of AIBN in dry toluene (20 mL) was added

n-Bu₃SnH (0.95 mL, 3.42 mmol) at 258C under argon. The

reaction mixture was stirred for 3 h, and extracted with

EtOAc. Usual workup gave deoxygenated compound 40

(540 mg, 62% from 38) as colorless gum. [a]²_D⁶111.9

Preparation of acetamide compound 44. To a solution of

41 (419 mg, 0.888 mmol) and PPh₃(279 mg, 1.06 mmol) in

dry THF (2 mL) were added diethyl azodicarboxylate

(0.42 mL, 40% in toluene, 1.1 mmol) and diphenyl-

phosphorylazide (0.29 mL, 1.3 mmol) at 08C under argon.

The reaction mixture was stirred at 08C for 2 h. The solvents

were removed under reduced pressure and the residue was

puri®ed by silica gel chromatography to give the azide 42

(650 mg) as pale yellow oil. To a solution of the crude azide

compound in MeOH (5 mL) was added SnCl₂(842 mg,

4.44 mmol) and stirred at 258C for 3 h. The solvent was

removed under reduced pressure and the residue was

acetylated with Ac₂O (1.5 mL) in pyridine (3.5 mL).

Usual workup gave acetamide 44 (302 mg, 66% from 41)

as colorless foam. [a]²_D⁷18.1 (c1.05, CHCl₃); H NMR

1

(270 MHz, CDCl₃) d 0.90 (3H, d, J6.6 Hz), 1.67 (3H, s),

2.25 (1H, dd, J6.6, 14.2 Hz), 2.33 (3H, s), 2.43 (1H, dd,

J8.3, 14.2 Hz), 3.60 (3H, s), 3.88 (3H, s), 3.96 (3H, s),

4.11±4.16 (1H, m), 4.86 (1H, d, J7.9 Hz), 5.25 (2H, s),

6.47 (1H, d, J2.3 Hz), 6.57 (1H, d, J2.3 Hz), 6.69 (2H,

s), 6.95 (1H, d, J7.9 Hz), 7.14 (1H, d, J7.9 Hz), 7.34

(1H, t, J6.9 Hz), 7.43 (2H, t, J6.9 Hz), 7.65 (2H, d,

J6.9 Hz); ¹³C NMR (67.5 MHz, CDCl₃) d 20.7, 22.2,

23.2, 39.4, 46.7, 55.3, 55.7, 56.1, 71.1, 97.1, 104.8, 107.1,

108.2, 116.3, 117.5, 122.4, 126.9, 127.4, 128.3, 129.4,

136.2, 136.7, 137.7, 139.9, 155.5, 157.3, 158.7, 159.9,

169.3; IR (CHCl₃) 3350, 2860, 1650, 1580 cm²¹; MS

(relative intensity) m/z 513 (M¹, 86), 454 (12), 423 (9),

380 (39), 363 (100), 348 (12); HRMS calcd for

C₃₂H₃₅NO₅513.2523, found 513.2519.

Preparation of naphthyltetrahydroisoquinoline com-

pound 46.

A solution of acetamide 44 (216 mg,

0.421 mmol) and POCl₃(0.12 mL, 1.3 mmol) in dry aceto-

nitrile (10 mL) was heated under re¯ux for 30 min under

argon. The reaction mixture was concentrated under

reduced pressure and the residue was extracted with

EtOAc, washed with 10% aqueous NaOH and brine.

Usual puri®cation gave cyclization product 45 (200 mg)

1

(c1.10, CHCl₃); H NMR (270 MHz, CDCl₃) d 20.31

(3H, s), 20.23 (3H, s), 0.75 (9H, s), 0.83 (3H, d,

J6.6 Hz), 2.33 (3H, s), 2.38 (2H, d, J6.6 Hz), 3.59

(1H, qui, J6.6 Hz), 3.60 (3H, s), 3.88 (3H, s), 3.95 (3H,

s), 5.23 (2H, s), 6.47 (1H, d, J2.3 Hz), 6.56 (1H, d,

J2.3 Hz), 6.67 (1H, s), 6.74 (1H, s), 6.92 (1H, d,

J7.9 Hz), 7.12 (1H, d, J7.9 Hz), 7.33±7.46 (3H, m),

7.63±7.65 (2H, m); IR (CHCl₃) 2925, 1580, 1460, 1370,

1320, 1160, 1070, 840 cm²¹; MS (relative intensity) m/z

586 (M¹, 87), 528 (7), 438 (31), 363 (84), 309 (100);

HRMS calcd for C₃₆H₄₆O₅Si 586.3133, found 586.3124.

1

as pale yellow foam. H NMR (270 MHz, CDCl₃) d 1.13

(3H, d, J6.6 Hz), 1.80 (1H, dd, J11.9, 16.2 Hz), 2.19

(1H, dd, J4.6, 16.2 Hz), 2.32 (3H, s), 2.52 (3H, d,

J1.6 Hz), 3.21±3.69 (1H, m), 3.70 (3H, s), 3.95 (3H, s),

3.97 (3H, s), 5.24 (2H, s), 6.51 (1H, s), 6.65 (1H, d), 6.68

(1H, s), 6.93 (1H, d, J7.9 Hz), 7.13 (1H, d, J7.9 Hz),

7.33 (1H, t, J7.9 Hz), 7.43 (2H, t, J7.9 Hz), 7.63 (2H,

d, J7.9 Hz); ¹³C NMR (67.5 MHz, CDCl₃) d 21.3, 22.1,

27.8, 31.7, 51.1, 55.5, 55.8, 56.2, 71.2, 93.8, 107.2, 108.4,

112.5, 116.4, 117.4, 120.4, 126.2, 126.9, 127.4, 128.3,

128.4, 136.2, 136.7, 137.8, 141.7, 155.7, 157.3, 158.4,

Preparation of 41. A solution of compound 40 (166 mg,

0.283 mmol) and n-Bu₄NF (0.85 mL, 1.0 M in THF,

0.85 mmol) in THF (3 mL) was stirred at 258C for 24 h.

Usual workup afforded 41 (128 mg, 97%) as colorless

2336

K. Kamikawa et al. / Tetrahedron 56 (2000) 2325±2337

160.1, 163.5. A solution of the crude product in dry THF

(5 mL) was added dropwise to a mixture of LiAlH₄

(169 mg, 4.40 mmol) and Et₃Al (2.20 mL, 2 M in hexane,

4.40 mmol) at 2788C. The suspension was stirred at 2788C

for 1 h, and warmed to 08C over 3 h. The reaction mixture

was quenched with saturated aqueous sodium ¯uoride and

the precipitate was ®ltered off. Usual workup gave 46

(158 mg, trans:cis93:7). This mixture was dissolved in

MeOH (2 mL), and treated with conc. HCl to transform it

to its hydrochloride salt. After evaporation of the solvent in

vacuo, the residue was recrystallized from CHCl₃/hexane. A

solution of the product in MeOH (2 mL) was treated with 30

% aqueous ammonia, extracted with EtOAc, and concen-

trated in vacuo to give 46 as light brown gum. [a]²_D³220.6

(c1.15, CHCl₃); ¹H NMR (270 MHz, CDCl₃) d 0.96 (3H,

d, J6.3 Hz), 1.46 (3H, d, J6.6 Hz), 1.75 (1H, br), 1.75

(1H, dd, J10.9, 17.2 Hz), 2.32 (1H, dd, J17.2, 4.0 Hz),

2.32 (3H, s), 3.16 (1H, m), 3.62 (3H, s), 3.92 (3H, s), 3.94

(3H, s), 4.44 (1H, q, J6.6 Hz), 5.24 (2H, s), 6.48 (1H, s),

6.67 (1H, d), 6.94 (1H, d, J7.9 Hz), 7.12 (1H, d,

J7.9 Hz), 7.33 (1H, t, J7.3 Hz), 7.42 (2H, t,

J7.3 Hz), 7.63 (2H, d, J7.3 Hz); ¹³C NMR (67.5 MHz,

CDCl₃) d 21.6, 22.1, 22.6, 35.0, 42.0, 47.3, 55.3, 56.2, 71.3,

93.3, 107.4, 108.4, 116.5, 117.6, 120.9, 121.3, 126.9, 127.4,

127.5, 128.1, 128.3, 136.0, 136.5, 138.0, 155.3, 156.1, 156.6

References

1. For representative reviews: (a) Bringmann, G.; Walter, R.;

Weirich, R. Angew. Chem. Int. Ed. Engl. 1990, 29, 977±991. (b)

Lutomski, K. A.; Meyers, A. I. Asymmetric Synthesis via Chiral

Oxazolines. In Asymmetric Synthesis; Morrison, J. D., Ed.;

Academic Press: New York, 1984; Vol. 3, pp 213±274. (c) Gant,

T. G.; Meyers, A. I. Tetrahedron 1994, 50, 2297±2360.

2. (a) Meyers, A. I.; Lutomski, K. A. J. Am. Chem. Soc. 1982, 104,

879±881. (b) Moorlang, H.; Meyers, A. I. Tetrahedron Lett. 1993,

34, 6989±6992. (c) Warshawsky, A. M.; Meyers, A. I. J. Am.

Chem. Soc. 1990, 112, 8090±8099.

3. (a) Nelson, T. D.; Meyers, A. I. Tetrahedron Lett. 1993, 34,

3061±3062. J. Org. Chem. 1994, 59, 2577±2580, 2655±2658. (b)

Nelson, T. D.; Meyers, A. I. Tetrahedron Lett. 1994, 35, 3259±

3262. (c) Degnan, A. P.; Meyers, A. I. J. Am. Chem. Soc. 1999,

121, 2762±2769.

4. (a) Hattori, T.; Hotta, H.; Suzuki, T.; Miyano, S. Bull. Chem.

Soc. Jpn 1993, 66, 613±622. (b) Baker, R. W.; Pocock, G. R.;

Sargent, M. V.; Twiss, E. Tetrahedron Asymmetry 1993, 4,

2423±2426. (c) Shindo, M.; Koga, K.; Tomioka, K. J. Am.

Chem. Soc. 1992, 114, 8732±8733.

5. (a) Tanaka, M.; Mitsuhashi, H.; Wakamatsu, T. Tetrahedron

Lett. 1992, 33, 4161±4164. (b) Evans, D. A.; Dinsmore, C. J.;

Evrard, D. A.; DeVries, K. M. J. Am. Chem. Soc. 1993, 115,

6426±6427. (c) Feldman, K. S.; Ensel, S. M. J. Am. Chem. Soc.

1993, 115, 1162±1673.

157.2; IR (CHCl₃) 3350, 2950, 1580, 1320, 1080, 920 cm²¹

;

MS (relative intensity) m/z 497 (M¹, 25), 482 (100), 402

(18), 391 (26); HRMS calcd for C₃₂H₃₅NO₄497.2594, found

497.2580.

6. Lipshutz, B. H.; Liu, Z.-P.; Kayser, F. Tetrahedron Lett. 1994,

35, 5567±5570.

7. (a) Brigmann, G.; Hartung, T. Synthesis 1992, 433±435. (b)

Bringmann, G.; Reuscher, H. Angew. Chem. Int. Ed. Engl. 1989,

28, 1672±1673.

Preparation of O,O⁰-dimethylkorupensamine A 47. A

solution of 46 (109 mg, 0.22 mmol) in 8.8% HCO₂H±

MeOH (2 mL) was added to palladium black (100 mg,

0.94 mmol) in 8.8% HCO₂H±MeOH (3 mL), and stirred

at 458C for 3 h under argon. After ®ltration the solution

was concentrated under reduced pressure. The residue was

dissolved in MeOH (2 mL) and treated with 30% aqueous

ammonia. The mixture was extracted with CH₂Cl₂. The

extract was washed with brine, dried over anhydrous

MgSO₄, and evaporated under reduced pressure to give

O,O⁰-dimethylkorupensamine A 47 (81 mg, 91%) as light

brown gum. [a]²_D²229.1 (c0.81, CHCl₃); ¹H NMR

(270 MHz, CDCl₃) d 0.95 (3H, d, J6.3 Hz), 1.45 (3H, d,

J6.6 Hz), 1.54 (1H, br), 1.70 (1H, dd, J10.9, 17.2 Hz),

2.31 (3H, s), 2.33 (1H, dd, J4.0, 17.2 Hz), 3.16 (1H, m),

3.62 (3H, s), 3.92 (3H, s), 4.04 (3H, s), 4.43 (1H, q,

J6.6 Hz), 6.47 (1H, s), 6.59 (1H, d), 6.68 (1H, d), 6.87

(1H, d, J7.9 Hz), 7.10 (1H, d, J7.9 Hz), 9.38 (1H, s); ¹³C

NMR (67.5 MHz, CDCl₃) d 21.7, 22.2, 22.8, 35.2, 41.9,

47.3, 55.3, 56.0, 56.1, 93.2, 106.2, 109.4, 113.5, 118.6,

121.0, 121.1, 125.2, 129.5, 135.4, 135.7, 136.2, 153.6,

156.0, 156.1 156.7; IR (CHCl₃) 3350, 2900, 1590, 1430,

1320, 1090 cm²¹; MS (relative intensity) m/z 407 (M¹, 9),

392 (100), 377 (7), 362 (17); HRMS calcd for C₂₅H₂₉NO₄

407.2061, found 407.2079.

8. (a) Hayashi, T.; Hayashizaki, K.; Kiyoi, T.; Ito, Y. J. Am. Chem.

Soc. 1988, 110, 8153±8156. (b) Hayashi, T.; Niizuma, S.;

Kamikawa, T.; Suzuki, N.; Uozumi, Y. J. Am. Chem. Soc. 1995,

117, 9101±9102.

Â

9. For some representative reviews: (a) Solladie-Cavallo, A. In

Advances in Metal-Organic Chemistry; Liebeskind, L. S., Ed.;

JAI Press: Greenwich, 1989; Vol. 1, pp 99±133. (b) Davies, S.

G.; Coote, S. J.; Goodfellow, C. L. In Advances in Metal-Organic

Chemistry; Liebeskind, L. S., Ed.; JAI Press: Greenwich, 1991;

Vol. 2, pp 1±57. (c) Uemura, M. In Advances in Metal-Organic

Chemistry; Liebeskind, L. S., Ed.; JAI Press: Greenwich, 1991;

Vol. 2, pp 195±245. (d) Semmelhack, M. F. In Comprehensive

Organometallic Chemistry II; Abel, E. D., Stone, F. G. A.,

Wilkinson, G., Eds.; Pergamon Press: Oxford, 1995; Vol. 12, pp.

979±1038. (e) Davies, S. G.; McCarthy, T. D. In Comprehensive

Organometallic Chemistry II; Abel, E. D., Stone, F. G. A.,

Wilkinson, G., Eds.; Pergamon Press: Oxford, 1995; Vol. 12, pp.

1039±1070.

10. Some representative references: (a) Uemura, M.; Miyake, R.;

Nakayama, K.; Shiro, M.; Hayashi, Y. J. Org. Chem. 1993, 58,

1238±1244. (b) Jones, G. B.; Huber, R. S.; Chapman, B. J.

Tetrahedron Asymmetry 1997, 8, 1797±1809. (c) Son, S. U.;

Jang, H.-Y.; Lee, I. S.; Chung, Y. K. Organometallics 1998, 17,

3236±3239.

11. (a) Scott, W. J. J. Chem. Soc., Chem. Commun. 1987, 1755±

1756. (b) Carpentier, J.-F.; Castanet, Y.; Brocard, J.; Mortreux, A.;

Petit, F. Tetrahedron Lett. 1991, 32, 4705±4708. (c) Carpentier,

J.-F.; Castanet, Y.; Brocard, J.; Mortreux, A.; Petit, F. Tetrahedron

Lett. 1992, 33, 2001±2004. (d) Mutin, R.; Lucas, C.; J. Thivolle-

Cazat, J. Dufaud, V.; Dany, F.; Basset, J. M. J. Chem. Soc., Chem.

Commun. 1988, 896±898. (e) Dufaud, V.; Thivolle-Cazat, J.;

Acknowledgements

This research was supported by a grant-in-aid for Scienti®c

Research from the Ministry of Education, Science, Sports

and Culture of Japan.

K. Kamikawa et al. / Tetrahedron 56 (2000) 2325±2337

2337

Basset, J. M.; Mathieu, R.; Jaud, J.; Waissermann, J. Organo-

metallics 1991, 10, 4005±4015.

24. Hallock, Y. F.; Manfredi, K. P.; Blunt, J. W.; Cardellina II,

È

J. H.; Schaffer, M.; Gulden, K.-P.; Bringmann, G.; Lee, A. Y.;

12. (a) Uemura, M.; Nishimura, H.; Kamikawa, K.; Nakayama,

K.; Hayashi, Y. Tetrahedron Lett. 1994, 35, 1909±1912. (b)

Uemura, M.; Kamikawa, K. J. Chem. Soc., Chem. Commun.

1994, 2697±2698. (c) Kamikawa, K.; Watanabe, T.; Uemura, M.

J. Org. Chem. 1996, 61, 1375±1384.

Clardy, J.; FrancËois, G.; Boyd, M. R. J. Org. Chem. 1994, 59,

6349±6355.

25. (a) Manfredi, K. P.; Blunt, J. W.; Cardellina II, J. H.;

McMahon, J. B.; Pannell, L. L.; Cragg, G. M.; Boyd, M. R.;

J. Med. Chem. 1991, 34, 3402±3405. (b) Boyd, M. R.; Hallock,

Y. F.; Cardellina II, J. H.; Blunt, J. W.; McMahon, J. B.; Buckheit,

13. The ®rst symbol indicates a con®guration of planar chirality of

the chromium complexed arene ring (at C-1 position), and the

p

second one represents the axial chirality. The symbol indicates

È

Jr., R. W.; Bringmann, G.; Schaffer, M.; Cragg, G. M.; Thomas,

D. W.; Jato, J. G. J. Med. Chem. 1994, 37, 1740±1745. (c)

McMahon, J. B.; Currens, M. J.; Gulakowski, R. J. R.; Buckheit,

Jr.,W.; Lackman-Smith, C.; Hallock, Y. F.; Boyd, M. R. Anti-

microb. Agents Chemother. 1995, 39, 484±488.

racemate, of which only one enantiomer is shown for clarity.

14. Watanabe, T.; Kamikawa, K.; Uemura, M. Tetrahedron Lett.

1995, 36, 6695±6698.

15. Kamikawa, K.; Watanabe, T.; Uemura, M. Synlett 1996,

1040±1042.

26. (a) Hoye, T. R.; Chen, M.; Mi, L.; Priest, O. P. Tetrahedron

Lett. 1994, 35, 8747±8750. (b) Hoye, T. R.; Mi, L. Tetrahedron

Lett., 1996, 37, 3097±3098. (c) Hoye, T. R.; Chen, M. Tetrahedron

Lett. 1996, 37, 3099±3100. (d) Hoye, T. R.; Chen, M. J. Org.

16. Kupchans, S. M.; Britton, R. W.; Ziegler, M. F.; Gilmore, C. J.;

Restivo, R. J.; Bryan, R. F. J. Am. Chem. Soc. 1973, 95, 1335±

1336.

È

Chem. 1996, 61, 7940±7942. (e) Bringmann, G.; Gotz, R.; Keller,

17. (a) Bradley, A.; Motherwell, W. B.; Ujjainwalla, F. J. Chem.

Soc., Chem. Commun. 1999, 917±918. (b) Narasimhan, N. S.;

Aiden, I. R. Tetrahedron Lett. 1988, 29, 2987±2988. (c) Meyers,

A. I.; Flisak, J. R.; Aitken, R. A. J. Am. Chem. Soc. 1987, 109,

5446±5452. (d) Magnus, P.; Schultz, J.; Gallagher. T. J. Am.

Chem. Soc. 1985, 107, 4984±4988. (e) Dhal, R.; Robin, J. P.;

Brown, E. Tetrahedron 1983, 39, 2787±2794. (f) Mervic, M.;

Ben-David, Y.; Ghera, E. Tetrahedron Lett. 1981, 22, 5091±

5094. (g) Ziegler, F. E.; Chliwner, I. C.; Fowler, K. W.; Kanfer,

S. J.; Kuo, S. J.; Sinha, N. D. J. Am. Chem. Soc. 1980, 102, 790±

798. (h) Brown, E.; Dhal, R.; Robin, J. P. Tetrahedron Lett. 1979,

29, 733±736. (i) Larson, E. R.; Raphael, R. A. Tetrahedron Lett.

1979, 5041±5042. (j) Krow, G. R.; Damadoran, K. M.; Michener,

E.; Wolf, R.; Gaure, J. J. Org. Chem. 1978, 43, 3950±3953. (k)

Becker, D.; Hughes, L. R.; Raphael, R. A. J. Chem. Soc., Perkin

Trans. 1 1977, 1674±1681. (l) Hughes, L. R.; Raphael, R. A.

Tetrahedron Lett. 1976, 29, 1543±1546. (m) Kende, A. S.;

Liebeskind, L. S. J. Am. Chem. Soc. 1976, 98, 267±268.

18. Uemura, M.; Daimon, A.; Hayashi, Y. J. Chem. Soc., Chem.

Commun. 1995, 1943±1944.

È

P. A.; Walter, R.; Henschel, P.; Schaffer, M.; Stablein, M.; Kelly,

T. R.; Boyd, M. R. Heterocycles 1994, 39, 503±508. (f) Hobbs,

P. D.; Upender, V.; Liu, J.; Pollart, D. J.; Thomas, D. W.; Dawson,

M. I. J. Chem. Soc., Chem. Commun. 1996, 923±924. (g) Hobbs,

P. D.; Upender, V.; Dawson, M. I. Synlett 1997, 965±967.

27. (a) Rizzacasa, M. A.; Sargent, M. V. J. Chem. Soc., Chem.

Commun. 1990, 894±896. (b) Leighton, B. N.; Rizzacasa, M. A.

J. Org. Chem. 1995, 60, 5702±5705.

28. Bringmann, G.; Breuning, M.; Tasler, S. Synthesis 1999, 525±

558.

29. Watanabe, T.; Uemura, M. J. Chem. Soc., Chem. Commun.

1998, 871±872.

30. Uemura, M.; Kobayashi, T.; Isobe, K.; Minami, T.; Hayashi, Y.

J. Org. Chem. 1986, 51, 2859±2863.

31. Mandal, S. K.; Sakar, A. J. Org. Chem. 1998, 63, 1901±1905.

32. Unfortunately, we did not succeed in the KH-mediated trans-

formation even in the literature compounds with DMF under

reported conditions.

33. Sharpless, K. B.; Amberg, W.; Bennani, Y. L.; Crispino, G. A.;

Hartung, J.; Jeong, K.-S.; Kwong, H.-L.; Morikawa, K.; Wang,

Z.-M.; Xu, D.; Zhang, X.-L. J. Org. Chem. 1992, 57, 2768±2770.

34. The corresponding di-MOM ether complex instead of

dimethoxy ether resulted in a regioiomeric 85:15 mixture of bromi-

nation complexes by ortho lithiation.

19. (a) Davies, S. G.; Goodfellow, C. L. J. Chem. Soc., Perkin

Trans. 1 1989, 192±194. (b) Davies, S. G.; Goodfellow, C. L.

Synlett 1989, 59±62.

20. Kondo, Y.; Green, J. R.; Ho, J. J. Org. Chem. 1993, 58, 6182±

6189.

35. Barton, D. H. R.; McCombie, S. W. J. Chem. Soc. Perkin

Trans. I 1975, 1574±1585.

36. Mitsunobu, O. Synthesis 1981, 1±28.

21. (a) Rychnovsky, S. D.; Plzak, K.; Pickering, D. Tetrahedron

Lett. 1994, 35, 6799±6802. (b) HungerbuÈhler, E.; Seebach, D.;

Wasmuth, D. Helv. Chim. Acta 1981, 64, 1467±1487. (c)

Pawlak, J.; Nakanishi, K.; Iwashita, T.; Borowski, E. J. Org.

Chem. 1987, 52, 2896±2901.

37. (a) Bringmann, G.; Jansen., R. J.; Rink, H.-P. Angew. Chem.

Int. Ed. Engl. 1986, 25, 913±915. (b) Bringmann, G.; Weirich, R.;

Reuscher, H.; Jansen, J. R.; Kinzinger, L.; Ortmann, T. Liebigs.

Ann. Chem. 1993, 877±888. (c) Maruoka, K.; Yamamoto, H.

Angew. Chem. Int. Ed. Engl. 1985, 24, 668±682.

22. Riant, O.; Samuel, O.; Kagan, H. B. J. Am. Chem. Soc. 1993,

115, 5835±5836.

23. Uemura, M.; Nishimura, H.; Kamikawa, K.; Shiro, M. Inorg.

Chim. Acta 1994, 222, 63±70.

Article Doi

Stereoselective synthesis of axially chiral natural products, (-)- steganone and O,O'-dimethylkorupensamine A, utilizing planar chiral (arene)chromium complexes

DOI: 10.1016/S0040-4020(99)01115-1

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Full text of DOI:10.1016/S0040-4020(99)01115-1

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