10.1021/ja043884l.s002
David A. Nicewicz
David A.
Nicewicz
Jeffrey S. Johnson
Jeffrey S.
Johnson
Three-Component Coupling Reactions of Silylglyoxylates, Alkynes, and
Aldehydes: A Chemoselective One-Step Glycolate Aldol Construction
American Chemical Society
2005
diol
adduct
diastereoselectivitie
presence
ee
silylgyloxylate
terminal alkynes
Aldehyde
variety
functionalized
zinc acetylide
chemoselective manner
Construction
aldehyde
methylephedrine
unoptimized
acetonide
Chemoselective
deprotection
glycolate
sequence
yield
Alkyne
Silylglyoxylate
Aldol
dr
ZnI 2
Et 3 N
Mechanistic experiments
Glycolate
silylglyoxylate
aldol
2005-05-04 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Three_Component_Coupling_Reactions_of_Silylglyoxylates_Alkynes_and_Aldehydes_A_Chemoselective_One_Step_Glycolate_Aldol_Construction/3288052
A single-pot three-component coupling reaction of silylglyoxylates (<b>1</b>), terminal alkynes, and aldehydes in the presence of ZnI<sub>2</sub> and Et<sub>3</sub>N is presented. The products of the reaction, densely functionalized silyl-protected glycolate aldols (<b>2</b>), can be converted to the corresponding acetonides (<b>3</b>) in a one-pot deprotection/ketalization sequence. A variety of terminal alkynes and aldehydes can be successfully employed to give a range of highly functionalized, fully protected 1,2-diols in good yields and moderate diastereoselectivities. Mechanistic experiments suggest that the zinc acetylide reacts with the silylgyloxylate (<b>1</b>) in a chemoselective manner. Using an unoptimized (+)-<i>N</i>-methylephedrine and Zn(OTf)<sub>2</sub> system, silyl-deprotected adduct <b>2</b> was formed in 64% ee and 89:11 dr.