The authors note that Figs. 1b, 1d, 1g, and 4a have been revised to include dividing lines between lanes to show where nonessential lanes were removed from a single original gel. Figs. 2c, 2d, and 3c have been revised to include boxes to indicate samples run on different gels, under the same conditions; these gels are aligned with respect to the indicated molecular weight markers. Figs. 4b and 4c have been revised to eliminate errors that occurred in the original version during file conversion. The changes were made to comply with the PNAS policy that requires dividing lines whenever entire nonessential lanes have been removed from a single original gel, and clear demarcation of samples run on separate gels. These changes do not affect the data presented nor the conclusions of the article. The corrected figures and their legends appear below.

No abstract

[chemical reaction: see text]. Aminomethyl polystyrene resin-bound linkers of p-acetoxybenzyl alcohol were subjected to reactions with diphosphitylating and triphosphitylating reagents to yield the corresponding polymer-bound diphosphitylating and triphosphitylating reagents, respectively. A number of unprotected carbohydrates and nucleosides were reacted with the polymer-bound reagents. Oxidation with tert-butyl hydroperoxide or sulfurization with Beaucage's reagent, followed by removal of cyanoethoxy group with DBU and the acidic cleavage, respectively, afforded only one type of monosubstituted nucleoside and carbohydrate diphosphates, dithiodiphosphates, triphosphates, and trithiotriphosphates with high regioselectivity.

Two classes of aminomethyl polystyrene resin-bound linkers of p-acetoxybenzyl alcohol were subjected to reactions with 2-cyanoethyl N,N-diisopropylchlorophosphoramidite to produce the corresponding polymer-bound phosphitylating reagents. These were reacted with a number of unprotected nucleosides and carbohydrates in the presence of 1H-tetrazole. Oxidation with tert-butyl hydroperoxide followed by removal of the cyanoethoxy group with 1,8-diazabicyclo[5.4.0]undec-7-ene afforded the corresponding polymer-bound phosphate diesters. Acidic cleavage of the p-acetoxybenzyl alcohol linker yielded monophosphorylated products with high regioselectivity and trapped linkers on the resins that can be reused.

Four classes of phosphitylating reagents were subjected to reactions with aminomethyl polystyrene resin-bound p-acetoxybenzyl alcohol to yield the corresponding polymer-bound mono-, di-, tri-, and tetraphosphitylating reagents. The solid-phase reagents were reacted with unprotected nucleosides (e.g., thymidine, adenosine, 3'-azido-3'-deoxythymidine, cytidine, or inosine) in the presence of 5-(ethylthio)-1H-tetrazole. Polymer-bound nucleosides underwent oxidation with tert-butyl hydroperoxide, deprotection of cyanoethoxy groups with DBU, and the acidic cleavage, respectively, to afford 5',5'-dinucleoside mono-, di-, tri-, and tetraphosphodiesters in 59-78% yield.