Iodonium Di-sym-collidine Perchlorate

[69417-67-0]  · C16H22ClIN2O4  · Iodonium Di-sym-collidine Perchlorate  · (MW 468.75)

(very reactive electrophile, superior source of I+,1 useful in the synthesis of cis-b-hydroxy amines,2 activates glycosides for glycosylation;5,6 can be used for iodolactonization12,13 and vicinal cis-diol14 preparation)

Alternate Name: IDCP.

Solubility: sol chloroform; insol ether.

Form Supplied in: fine colorless crystalline powder. Drying: see Bromonium Di-sym-collidine Perchlorate.

Handling, Storage, and Precautions: see Bromonium Di-sym-collidine Perchlorate.


IDCP (1) is useful in the synthesis of cis-hydroxyamino sugars, e.g. methyl N-acetylristosaminide has been obtained from an oxazoline which can be made by the reaction of a trichloromethyl imidate with IDCP. The imidate can be prepared by reaction of the corresponding allylic alcohol with Trichloroacetonitrile in presence of Sodium Hydride (eq 1).

The synthesis of methyl a,L-garosaminide,3 a key component of aminocyclitol antibiotics, is complicated by the presence of a cis-hydroxyamino group and by the tertiary character of the hydroxy group. The problems have been resolved by use of the allylic epoxide as starting material. This epoxide was converted in three steps into an allylic amine. Treatment of iodonium salt gave the iodooxazolidinone in 82% yield. The product was reduced and the ethoxy ethyl group was removed and finally converted to the desired product by hydrolysis (eq 2).

Similar methodology can convert an internal allylic amine into a cis-b-hydroxyamine, as illustrated in a synthesis of holacosamin, a component of some glycosteroids (eq 3).4

a-Linked Disaccharides.5

The reagent functions as a superior source of I+, probably because of the nonnucleophilic counterion. Thus a pyranoid diene reacts with IDCP to give a planar ion to which an alcohol adds in a 1,4-sense to give an a-glycoside. Thus tetraacetylfructose reacts to give an a-disaccharide in 45% yield (eq 4). The b-isomer is not detected.

Examples are known where this reagent has activated pent-4-enyl glycosides for glycosylation,6 but a- and b-glycosides were obtained in various proportions regardless of the nature of donors or acceptors (primary or secondary hydroxyl groups). Glycosylations of 1,2:5,6-di-O-isopropylidene-a-D-galactopyranose and methyl 2,3,4-tri-O-benzyl-a-D-glucopyranoside were investigated with pent-4-enyl-2,3,4-tri-O-benzyl-b-D-glucopyranoside derivatives in which 6-OH was protected by a benzyl, a trityl, or a TBDMS group in order to assess the effect of the bulk of the 6-substituents. The presence of a bulky 6-substituent (a) increases significantly the proportion of the a-product; (b) decreases the yield when a secondary hydroxy group is glycosylated, but the effect is less or opposite when a primary hydroxy group is involved; (c) lowers the increase in yield of the a-product when a primary hydroxy group is glycosylated; (d) gives a much better yield of the a-anomer when there is a higher proportion of ether in the solvent.

Chemospecific glycosidation of partially benzoylated thioglycosides (disarmed acceptors) with perbenzylated thioglycosides (armed donors) can be realized in the presence of the promotor IDCP (eq 5).7

Reaction of IDCP with unsaturated alcohols and carboxylic acids in dichloromethane at ambient temperature has afforded three- to seven-membered ring iodoethers and four- to seven-membered ring iodolactones, respectively, in moderate yields and generally with high regioselectivity. The reaction has particular utility for synthesis of 2-(1-iodoalkyl)oxiranes and -oxetanes.11 Glycosylation has also been achieved by electrophile-induced activation of anomeric O-glycosyl N-allyl carbamates (eq 6).8

Treatment of fully benzylated 1-methylene-D-glucose with IDCP gives easy access to 1-iodoheptuloses or a 1-iodomethylene derivative.9 The latter compound is, in turn, further amenable to similar IDCP-mediated addition reaction. In the synthesis of ciclamycin O the required trisaccharide glycol was assembled by substituent-directed iodinative coupling of glycals as shown in (eq 7).10

Iodolactonization of heptadienoic acid derivatives having oxazolidin-2-ones or a sultam12 as chiral auxiliary gave the chiral iodolactone with moderate to excellent enantioselectivity.13

Vicinal cis-Diols.14

An allylic alcohol is converted into its primary urethane derivative, which is then subjected to iodonium ion induced cyclization to give a single iodocarbonate. The carbonate is then deiodinated reductively and hydrolyzed to afford the vicinal diol.

1. Lemieux, R. U.; Morgan, A. R. CJC 1965, 43, 2190.
2. Pauls, H. W.; Fraser-Reid, B. JOC 1983, 48, 1392.
3. Pauls, H. W.; Fraser-Reid, B. JACS 1980, 102, 3956.
4. George, M.; Fraser-Reid, B. TL 1981, 22, 4635.
5. Fraser-Reid, B.; Iley, D. E. CJC 1979, 57, 645.
6. Houdier, S.; Voltero, P. J. A. Carbohydr. Res. 1992, 232, 349.
7. (a) Veeneman, G. H.; Van Boom, J. H. TL 1990, 31, 275. (b) Veeneman G. H.; Van Leeuwen, S. H.; Van Boom, J. H. TL 1990, 31, 1331.
8. Kuns, H.; Simmer, J. TL 1993, 34, 2907.
9. Noort, D.; Veeneman, G. H.; Boons, G. P. H.; Vander Marel, G. A.; Mulder, G. J.; Van Boom, J. H. SL 1990, 205.
10. Susuki, K.; Sulikowski, G. A.; Friesen, R. W.; Danishefsky, S. J. JACS 1990, 112, 8895.
11. Evans, R. D.; Magee, J. W.; Schauble, J. H. S 1988, 862.
12. Oppolser, W.; Chapuis, C.; Bernardielli, G. HCA 1984, 67, 1397.
13. Yokomatsu, T.; Iwasawa, H.; Shibuya, S. CC 1992, 510.
14. Pauls, H. W.; Fraser-Reid, B. J. Carbohydr. Chem. 1985, 4, 1.

Tapan Ray

Sandoz Research Institute, East Hanover, NJ, USA

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