Carbohydrate Research, 230 (1992) 289-297 Elsevier Science Publishers B.V., Amsterdam 289 Regioselectivity of the insertion reactions of some aromatic diazo compound complexes with cyclomaltoheptaose Shelley H. Smith, Sarah M. Forrest, David C. Williams, Jr., Margaret F. Cabell, Michael F. Acquavella and Christopher J. Abelt Department of Chemistry, The College of W illiam and Mary in Virginia, W illiamsburg, Virginia 23185 zyxwvutsrqponm (USA) (Received July 17th, 1991; accepted November 29th, 1991) ABSTRACT Pyrolysis of solid complexes of aromatic diazo compounds with cyclomaltoheptaose (p-cyclodextrin) yields ether derivatives via insertion of carbene into hydroxyl groups. The distribution of the 2-, 3-, and GO-isomers indicates that the regioselectivity is moderate. The guest geometry is not as important as its size in determining the ratios of regioisomers. The origins of the regioselectivity are discussed. INTRODUCTION The chemical modification of cyclomalto-oligosacchardes (cyclodextrins, CDs) is a popular approach for the construction of enzyme models’. Regiochemical control in the synthesis of CD derivatives is difficult, but is possible with pCD by way of sulfonates’. Thus, the reactions of tosyl chloride2”, m-nitrophenyl p-toluene- sulfonate2b, and 2-naphthylsulfonyl chloride2c with PCD give the corresponding 6-, 2-, and 3-sulfonates. In the first reaction, the tosyl chloride is solvated and reacts with the most available hydroxyl groups, i.e., HO-6. The last two reactions proceed via an inclusion complex which restricts the reactive sulfur center to be near the face of the secondary hydroxyl groups (HO-2,3) of the glucose residues. Since the complexation of a reactant with PCD in solution can give high regioselectivity, we wondered if reactions conducted in solid PCD complexes might also provide selectivity. The pyrolysis of several aromatic diazo compounds, PhCHN,, PhC(CH,)N,, and Ph,CN,, complexed with OCD, results in the forma- tion of mono-ether derivatives 3. We have now investigated reactions of other complexes of PCD with aromatic diazo compounds in order to determine how the Correspondence to: Professor C.J. Abelt, Department of Chemistry, The College of William and Mary in Virginia, Williamsburg, VA 23185, USA. OOOS-6215/92/$05.00 0 1992 - Elsevier Science Publishers B.V. All rights reserved