10.1021/jo9018446.s001
Yang Yue
Yang
Yue
Mark Turlington
Mark
Turlington
Xiao-Qi Yu
Xiao-Qi
Yu
Lin Pu
Lin
Pu
3,3′-Anisyl-Substituted BINOL, H<sub>4</sub>BINOL, and H<sub>8</sub>BINOL Ligands: Asymmetric Synthesis of Diverse Propargylic Alcohols and Their Ring-Closing Metathesis to Chiral Cycloalkenes
American Chemical Society
2009
H 4BINOL
ee
alkyne
H 8BINOL derivatives
Diverse Propargylic Alcohols
H 8BINOL Ligands
Grubbs II catalyst
chemoselective tandem RCM hydrogenation reaction
chiral propargylic alcohols
Chiral CycloalkenesA series
2009-11-20 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/3_3_Anisyl_Substituted_BINOL_H_sub_4_sub_BINOL_and_H_sub_8_sub_BINOL_Ligands_Asymmetric_Synthesis_of_Diverse_Propargylic_Alcohols_and_Their_Ring_Closing_Metathesis_to_Chiral_Cycloalkenes/2811601
A series of optically active BINOL, H<sub>4</sub>BINOL, and H<sub>8</sub>BINOL derivatives were prepared. These compounds in combination with ZnEt<sub>2</sub> and Ti(O<sup><i>i</i></sup>Pr)<sub>4</sub> were used to catalyze the asymmetric reaction of alkynes with aldehydes to generate chiral propargylic alcohols at room temperature. Through this comparative study, a 3,3′-bisanisyl-substituted H<sub>8</sub>BINOL (<i>S</i>)-<b>7</b> was found to be a generally enantioselective catalyst for the reaction of structurally diverse terminal alkynes with a variety of aldehydes. It catalyzed the reactions of alkyl propiolates with 88−99% ee; the reactions of phenylacetylene with 81−87% ee; the reactions of 4-phenyl-1-butyne, an alkyl alkyne, with 77−89% ee; and the reactions of trimethylsilylacetylene with 92−97% ee. The optically active propargylic alcohols generated from this catalytic asymmetric alkyne addition were observed to undergo efficient ring-closing-metathesis (RCM) reaction in the presence of the Grubbs II catalyst to produce chiral cycloalkenes. It was further found that some of the chiral propargylic alcohols underwent a highly chemoselective tandem RCM hydrogenation reaction with retention of the enantiomeric purity.