​9. Shi, J.; Shigehisa, H.; Guerrero, C. A.; Shenvi, R. A.; Li, R. A.; Baran, P. S. Stereodivergent Synthesis of 17-α and 17-β-Aryl Steroids: Application and Biological Evaluation of D-Ring Cortistatin Analogues. Angew. Chem. Int. Ed. 2009, 48, 4328-4331.