An optically active 2,3-bis(dialkylphosphino)pyrazine derivative represented by formula (1) is disclosed. The pyrazine derivative is preferably a quinoxaline derivative represented by formula (2). In formula (1) and (2), R.sup.1 is preferably a t-butyl or adamantyl group, and R.sup.2 is preferably a methyl group. ##STR00001## wherein R.sup.1 is a substitutable straight chain or branched alkyl group having 2 to 10 carbon atoms; R.sup.2 is a substitutable straight chain or branched alkyl group having fewer carbon atoms than R.sup.1; and R.sup.3 and R.sup.4, which may be the same or different, are each a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, or R.sup.3 and R.sup.4 are taken together to form a saturated or unsaturated ring. ##STR00002## wherein R.sup.1 and R.sup.2 are as defined above; and R.sup.5 is a monovalent substituent.