Highly enantioselective addition of linear alkyl alkynes to aromatic aldehydes

An asymmetric linear alkyl alkyne addition to aromatic aldehydes catalyzed by the Ti-(R)-BINOL system is reported with high enantioselectivity and yield. Our study expands upon the synthetic scope of propargylic alcohols, which could serve as potentially useful intermediates for the synthesis of various natural products.

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(S)-1-Phenyl-non-2-yn-1-olC15H20O[α]D20=-100.4 (c 0.91, CHCl3)Source of chirality: (R)-1, 1′-bi-2-naphtholAbsolute configuration: (S)

(S)-1-(2-Methylphenyl)-non-2-yn-1-olC16H22O[α]D20=-29.4 (c 0.50, CHCl3)Source of chirality: (R)-1, 1′-bi-2-naphtholAbsolute configuration: (S)

(S)-1-(3-Methylphenyl)-non-2-yn-1-olC16H22O[α]D20=-14.9 (c 0.50, CHCl3)Source of chirality: (R)-1,1′-bi-2-naphtholAbsolute configuration: (S)

(S)-1-(4-Methylphenyl)-non-2-yn-1-olC16H22O[α]D20=-23.0 (c 0.50, CHCl3)Source of chirality: (R)-1, 1′-bi-2-naphtholAbsolute configuration: (S)

(S)-1-(3-Methoxyphenyl)-non-2-yn-1-olC16H22O2[α]D20=-56.1 (c 0.50, CHCl3)Source of chirality: (R)-1, 1′-bi-2-naphtholAbsolute configuration: (S)

(S)-1-(4-Methoxyphenyl)-non-2-yn-1-olC16H22O2[α]D20=-59.7 (c 0.50, CHCl3)Source of chirality: (R)-1, 1′-bi-2-naphtholAbsolute configuration: (S)

(S)-1-(3-Fluorophenyl)-non-2-yn-1-olC15H19FO[α]D20=-54.4 (c 0.88, CHCl3)Source of chirality: (R)-1, 1′-bi-2-naphtholAbsolute configuration: (S)

(S)-1-(3-Chlorophenyl)-non-2-yn-1-olC15H19OCl[α]D20=-73.6 (c 1.00, CHCl3)Source of chirality: (R)-1, 1′-bi-2-naphtholAbsolute configuration: (S)

(S)-1-(3-Bromophenyl)-non-2-yn-1-olC15H19OBr[α]D20=-44.3 (c 0.45, CHCl3)Source of chirality: (R)-1, 1′-bi-2-naphtholAbsolute configuration: (S)

(S)-1-(2-Chlorophenyl)-non-2-yn-1-olC15H19OCl[α]D20=+25.5 (c 0.95, CHCl3)Source of chirality: (R)-1, 1′-bi-2-naphtholAbsolute configuration: (S)

(S)-1-(4-Fluorophenyl)-non-2-yn-1-olC15H19OF[α]D20=-18.0 (c 0.52, CHCl3)Source of chirality: (R)-1, 1′-bi-2-naphtholAbsolute configuration: (S)

(S)-1-Phenyl-hept-2-yn-1-olC13H16O[α]D20=-54.1 (c 0.79, CHCl3)Source of chirality: (R)-1, 1′-bi-2-naphtholAbsolute configuration: (S)

(S)-1-(4-Methylphenyl)-hept-2-yn-1-olC14H18O[α]D20=-67.4 (c 1.05, CHCl3)Source of chirality: (R)-1, 1′-bi-2-naphtholAbsolute configuration: (S)

(S)-1-(3-Methoxyphenyl)-hept-2-yn-1-olC14H18O2[α]D20=-63.2 (c 1.02, CHCl3)Source of chirality: (R)-1, 1′-bi-2-naphtholAbsolute configuration: (S)

(S)-1-(3-Fluorophenyl)-hept-2-yn-1-olC13H15FO[α]D20=-49.0 (c 0.97, CHCl3)Source of chirality: (R)-1, 1′-bi-2-naphtholAbsolute configuration: (S)