Palladium-catalyzed carbonylative annulation technology has been recognized as a useful synthetic tool for heterocyles, which play an important role as a basic unit for the design of many pharmacologically and biologically active compounds. As part of our continuing studies directed towards transition metal-catalyzed cyclization reactions, we also recently reported on the synthesis of various heterocycles such as isoindolinones, β-lactams, and phthalides via palladium-catalyzed carbonylative cyclization. Among them, in connection with this report, 2-bromobenzaldehyde was found to be cyclized with primary alcohols in the presence of a palladium catalyst and a base under carbon monoxide pressure to afford 3-alkoxy-3H-isobenzofuran-1ones. Such a similar annulation using 2-bromobenzaldehydes leading to carboand heterocycles was also exemplified by us and others. Under these circumstances, the present work was disclosed during the course of the extension of this protocol to the reaction with 3-bromopyridine-4-carbaldehyde (2), which is readily prepared from 3-bromopyridine (1) via reported method (Scheme 1). Herein this report describes a new entry for 1-alkoxy-1H-furo[3,4-c]pyridine3-ones 4 via intrinsic palladium-catalyzed three-component tethering. The present reaction was intrinsically carried out with similar catalytic system based on our recent report on palladium-catalyzed synthesis of 3-alkoxy-3H-isobenzofuran-1-ones from 2-bromobenzaldehyde and primary or secondary alcohols under carbon monoxide pressure. Generally, 3-bromopyridine-4-carbaldehyde (2) was subjected to react with 5 equiv. of a primary or secondary alcohol 3 in THF at 100 C in the presence of a catalytic amount of PdCl2(PPh3)2 (2 mol% based on 2) and NaHCO3 under carbon monoxide pressure to afford 1-alkoxy-1H-furo[3,4c]pyridine-3-ones 4 (Scheme 1). The reaction was monitored until 2 had disappeared on TLC, which occurred within 20 h. The reaction of 2 with various primary or secondary alcohols 3 was screened in order to investigate the reaction scope and several representative results are summarized in Table 1. As shown in Table 1, 2 was readily tethered with an array of primary alcohols 3a-g having straight and branched alkyl chains and carbon monoxide to give the corresponding 1-alkoxy-1H-furo[3,4-c]pyridine-3-ones 4a-g in the range of 40-71% yields. The product yield was increased with the chain length of straight primary alcohols, whereas the position of branching of branched primary alcohols had no relevance to the product yield. In the reaction with 2methylbutan-1-ol (3g), the product 4g was obtained as a diastereoisomeric mixture. As is the case for the cyclization with 2-bromobenzaldehyde, in the reaction with benzyl alcohol (3h), a lower product yield was observed when compared with 3a-g. The reaction proceeds likewise with secondary alcohols (3i and 3j) to afford the corresponding 1alkoxy-1H-furo[3,4-c]pyridine-3-ones (4i and 4j) and the product yield was generally lower than that when primary alcohols were used. In summary, it has been shown that 3-bromopyridine-4carbaldehyde undergoes tethering with primary alcohols as well as secondary alcohols under carbon monoxide pressure in the presence of a catalytic amount of a palladium catalyst along with a base to afford 1-alkoxy-1H-furo[3,4-c]pyridine-3-ones in moderate to good yields. The present reaction provides a new entry for phthalide analogue, 1-alkoxy-1Hfuro[3,4-c]pyridine-3-ones.