Cimilophytine, a new bisindole alkaloid of the aspidosperma-canthinone structural class, isolated from Haplophyton cimicidum (Apocynaceae), has been assigned structure l. The structures of a number of indole alkaloids from Haplophyton cimicidum have been reported from our laboratory. Two of these alkaloids, cimiciphytine (2) and norcimiciphytine (3) were isolated by subjecting the alkali-soluble base residues from the isolation of haplophytine (4), the major alkaloid of H. cimicidum, to pH gradient countercurrent distribution. We now report the structure of another new bisindole alkaloid, cimilophytine (l), which we have isolated from the same alkali-soluble base residues; The fungus Rhizopus nigricans has been used to effect the enantioselective hydrolysis of 22 acetates of acyclic 1-arylalkanols. The absolute stereochemistry of all the chiral alcohols formed can be accounted for by a rule which is based on the relative sizes of substituents on the carbinol carbon. The relative sizes of substituents deduced from these hydrolyses have been compared with those assigned from Horeau's method for the same compounds and found to be identical; i.e., a phenyl group or heterocyclic ring is always larger than an alkyl group. The use of R. nigricans to prepare chiral alcohols and use of the rule to predict their configuration constitute a new method of assigning the absolute stereochemistry of secondary alcohols. With minor modifications this method can also be used to prepare gram quantities of chiral alcohols of both configurations.