| abstract |
A novel thiophene compound which is an intermediate useful for the efficient production of caffenofuran or an analogue thereof. Also provided is a process for producing caffenofuran or an analogue thereof via the novel thiophene compound as an intermediate. The novel thiophene compound is represented by the following formula (1): [wherein R1 represents hydrogen or C1-4 alkyl; R2 represents hydrogen or an alcohol-protecting group; and R3 represents hydrogen or a group represented by -COR4 or -C(OH)R5 (wherein R4 and R5 each represents C1-4 alkyl), provided that when R2 and R3 are hydrogen, then R1 is none of hydrogen, methyl, and n-propyl]. A thiophene compound represented by the following formula (2), among the compounds of the formula (1), is reduced and cyclized in the presence of a transition metal catalyst to produce caffenofuran or an analogue thereof (3a) as shown below. [Chemical formula 2] H2 (2) → (3) (In the formulae, R1 represents hydrogen or C1-4 alkyl; and R4 represents C1-4 alkyl.) |