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.
Tetrahedron
; 67(35): 6497-6512, 2011 Sep 02.
Article
em En
| MEDLINE
| ID: mdl-21857752
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. >201), and (E)/(Z) selectivity (>201). This new method was applied to the synthesis of the C(23)-C(40) fragment 2 of tetrafibricin.
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01-internacional
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MEDLINE
Idioma:
En
Ano de publicação:
2011
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Article