Application of the lithiation–borylation reaction to the rapid and enantioselective synthesis of the bisabolane family of sesquiterpenes
作者:Varinder K. Aggarwal、Liam T. Ball、Simon Carobene、Rickki L. Connelly、Matthew J. Hesse、Benjamin M. Partridge、Philippe Roth、Stephen P. Thomas、Matthew P. Webster
DOI:10.1039/c2cc32176a
日期:——
The expedient enantioselective synthesis of 5 bisabolane sesquiterpenes has been achieved using a common, one-pot lithiation-borylation reaction of secondary benzylic carbamates and either protodeboronation or oxidation to give the natural products in fewer than 5 steps, with high yield and >94 : 6 er.
Protodeboronation of Tertiary Boronic Esters: Asymmetric Synthesis of Tertiary Alkyl Stereogenic Centers
作者:Stefan Nave、Ravindra P. Sonawane、Tim G. Elford、Varinder K. Aggarwal
DOI:10.1021/ja1084207
日期:2010.12.8
tertiary boranes undergo efficient protodeboronation with carboxylic acids, tertiary boronicesters do not. Instead, we have discovered that CsF with 1.1 equiv of H2O (on tertiary diarylalkyl boronicesters) or TBAF·3H2O (on tertiary aryldialkyl boronicesters) effect highly efficient protodeboronation of tertiary boronicesters with essentially complete retention of configuration. Furthermore, substituting
Regio- and Enantiospecific Rhodium-Catalyzed Allylic Substitution with an Acyl Anion Equivalent
作者:P. Andrew Evans、Samuel Oliver
DOI:10.1021/ol402336u
日期:2013.11.15
The construction of enantiomerically enriched acyclic quaternary substituted ketones via the regio- and enantiospecific rhodium-catalyzed allylic alkylation reaction of chiral nonracemic tertiary alcohols with cyanohydrin pronucleophiles is described. This approach provides an alternative method to the α-arylation and vinylation of acyclic disubstituted ketone enolates, which remains a challenging
Total Synthesis of (+)-Erogorgiaene Using Lithiation–Borylation Methodology, and Stereoselective Synthesis of Each of Its Diastereoisomers
作者:Tim G. Elford、Stefan Nave、Ravindra P. Sonawane、Varinder K. Aggarwal
DOI:10.1021/ja207869f
日期:2011.10.26
A short (8 steps) synthesis of (+)-erogorgiaene in 44% overall yield from p-methylacetophenone is described. Key steps include lithiation/borylation-protodeboronation to build up the molecule and control the stereochemistry at C1 and C4. The C11 stereochemistry was similarly set up by using lithiation/borylation methodology. The use of a mixed, unhindered borane in the lithiation/borylation reaction