2-Di-t-butylphosphino-4-methoxy-3.5.6-trimethyl-2'.4'.6'-tri-i-propyl)-1.1'-biphenyl. min. 98% [~1:1 mixture with regioisomer. 2-Di-t-butylphosphino-5-methoxy-3.4.6-trimethyl-2'.4'.6'-tri-i-propylbiph