A short, protecting group-free total synthesis of bruceollines D, E, and J.

ABSTRACT

A short, protecting group-free total synthesis of bruceollines D, E, and J has been achieved. The enantioselective reduction of bruceolline E with ß-chlorodiisopinocampheylborane delivers both the natural and unnatural enantiomers of bruceolline J in excellent yields and enantioselectivities. Reduction with baker's yeast and sucrose was shown to provide the unnatural enantiomer of bruceolline J in 98% ee.