Synthesis of Gossypol Analogues

Abstract

Abstract Two gossypol analogues 2a and 2b were synthesized for biological evaluation as male contraceptive agents. The naphthol 8c was prepared by analogy with a known procedure starling from 3‐isopropylcatechol ( 3 ). ( t ‐Bu) 2 O 2 ‐Mediated phenolic coupling of 8c furnished the binaphthol 9c which, after pyrane ring closure, deprotection. and selective bisformylation with SnCl 4 /Cl 2 CHOCH 3 , gave the target compound 2a . The corresponding tetrahydroxy analogue 2b was prepared in a similar way.