Development of a double allylboration reagent targeting 1,5-syn-(E)-diols: application to the synthesis of the C(23)-C(40) fragment of tetrafibricin

Academic Article
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related to degree

  • Lira, Ricardo, Ph.D. in Chemistry, Scripps Research , Transferred from University of Michigan with advisor 2005 - 2008

publication date

  • September 2011

abstract

  • Interest in the synthesis of the C(23)-C(40) fragment 2 of tetrafibricin prompted us to develop a new method for the synthesis of 1,5-syn-(E)-diols. Toward this end, the kinetically controlled hydroboration of allenes 6, 33, ent-39, 42 and 45 with the Soderquist borane 25R were studied. Tetrabutylammonium allenyltrifluoroborate 45 gave superior results and was utilized in a double allylboration sequence with two different aldehydes to provide the targeted 1,5-syn-(E)-diols in generally high yields (72-98%), and with high enantioselectivity (>95% e.e.), diastereoselectivity (d.r. >20:1), and (E)/(Z) selectivity (>20:1). This new method was applied to the synthesis of the C(23)-C(40) fragment 2 of tetrafibricin.