4-Trimethylsilyl-3-butyn-2-ol

Chemical Properties

Colorless liquid

Physical properties

bp 83–85°C (13 mmHg).

Uses

More recently, Mulzer has reported use of the corresponding allenylsilane derived from 4-TMS-3-butyn-2-ol for use in the synthesis of the C13–C18 fragment of branimycin (eq 2).

Preparation

racemic 4-trimethylsilyl-3-butyn-2-ol can be prepared by deprotonation with strong bases (BuLi, LDA, Grignards reagents) of trimethylsilylacetylene followed by addition to acetaldehyde.Deprotonation of 3-butyn-2- ol followed by quenching with excess trimethylsilyl chloride followed by concomitant hydrolysis of the trimethylsilyl ether is generally the most straightforward route.Enzymatic reduction of 4-TMS-3-butyn-2-one has also been used to prepare the reagent using alcohol dehydrogenase.
Preparation of nonracemic 4-TMS-3-butyn-2-ol has been accomplished by asymmetric addition of dimethylzinc to acetaldehyde promoted by TADDOL or addition of a trimethylsilylvinylsulfoxide to acetaldehyde followed by thermal elimination of the sulfoxide.Asymmetric reduction of 4- TMS-3-butyn-2-one using stoichiometric reducing reagents, catalytic transfer hydrodrogenation,and enzymatic reduction with isolated protein or whole cells afford the 4-TMS-3-butyn- 2-ol with varying degrees of enantioenrichment.Enzymatic resolution by esterification of the racemic alcohol is the method of choice for the large-scale preparation.