Asymmetric indium-mediated synthesis of homopropargylic alcohols
作者:Lacie C. Hirayama、Kevin K. Dunham、Bakthan Singaram
DOI:10.1016/j.tetlet.2006.05.049
日期:2006.7
A method for the enantioselective synthesis of homopropargylicalcohols using indium under Barbier-like conditions is reported herein. Both aromatic and aliphatic aldehydes were successfully converted to the corresponding homopropargylicalcohols in good yield and high enantiomeric excesses using propargyl bromide, indium, and (1S,2R)-(+)-2-amino-1,2-diphenylethanol as a chiral auxiliary.
Direct Synthesis of <i>B</i>-Allyl and <i>B</i>-Allenyldiisopinocampheylborane Reagents Using Allyl or Propargyl Halides and Indium Metal Under Barbier-Type Conditions
作者:Lacie C. Hirayama、Terra D. Haddad、Allen G. Oliver、Bakthan Singaram
DOI:10.1021/jo300260a
日期:2012.5.4
groups to aldehydes and ketonesusing B-chlorodiisopinocampheylborane (dDIP-Cl) and indium metal. Under Barbier-type conditions, indium metal was used to generate allyl- and allenylindium intermediates, and subsequent reaction with dDIP-Cl successfully promoted the transfer of these groups to boron forming the corresponding chiralboranereagents. The newly formed boranereagents were reacted with aldehydes
Catalytic Enantioselective Cr-Mediated Propargylation: Application to Halichondrin Synthesis
作者:Songbai Liu、Joseph T. Kim、Cheng-Guo Dong、Yoshito Kishi
DOI:10.1021/ol9016595
日期:2009.10.15
Amano-lipase, this method provides a practical synthesis of optically pure 8 on a multigram scale. With maintenance of its optical purity, 8 has been converted to 1b, the C14−C19 building block of halichondrins and E7389, in two steps.
Nonracemic Homopropargylic Alcohols via Asymmetric Allenylboration with the Robust and Versatile 10-TMS-9-borabicyclo[3.3.2]decanes
作者:Chunqiu Lai、John A. Soderquist
DOI:10.1021/ol0476164
日期:2005.3.1
The asymmetric allenylboration of representative aldehydes with the stable, storable 1 is reported. Easily and efficiently prepared in either enantiomeric form from the air-stable crystalline 4 through simple Grignard procedures, 1 gives 6 cleanly. The latter is easily isolated in high yield and ee with predictable stereochemistry. The procedure also regenerates 4 for its direct conversion back to
Indium-Mediated Asymmetric Barbier-Type Propargylations: Additions to Aldehydes and Ketones and Mechanistic Investigation of the Organoindium Reagents
作者:Terra D. Haddad、Lacie C. Hirayama、Jannise J. Buckley、Bakthan Singaram
DOI:10.1021/jo201980b
日期:2012.1.20
acid indium triflate [In(OTf)3] induced regioselective formation of the corresponding homoallenic alcohol product from acetophenone. However, this methodology demonstrated excellent chemoselectivity in formation of only the corresponding secondary homopropargylic alcohol product in the presence of a ketone functionality. Investigation of the organoindium intermediates under our reaction conditions shows