Simple procedures for the preparation of (Z)-2-(1-trimethylsilyl-1-alkenyl)-1,3,2-dioxaborinanes

✍ Scribed by Narayan G Bhat; Claudia P Aguirre

• Publisher: Elsevier Science
• Year: 2000
• Tongue: French
• Weight: 67 KB
• Volume: 41
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)01405-2

✦ Synopsis

Two simple procedures for obtaining (Z)-2-(1-trimethylsilyl-1-alkenyl)-1,3,2-dioxaborinanes based on 1-trimethylsilyl-1-alkynes are described. In the first procedure, 1-trimethylsilyl-1-alkynes are hydroborated with diisopinocampheylborane to provide the corresponding (Z)-2-(trimethylsilyl-1-alkenyl)-diisopinocampheylboranes. These are then reacted with excess acetaldehyde to afford the corresponding (Z)-2-(1trimethylsilyl-1-alkenyl)-diethoxyboranes which are esterified with 1,3-propane diol to give the (Z)-2-(1trimethylsilyl-1-alkenyl)-1,3,2-dioxaborinanes in good yields and in high stereochemical purities. In the second procedure, 1-trimethylsilyl-1-alkynes are hydroborated with dichloroborane-methyl sulfide complex in the presence of a stoichiometric amount of boron trichloride in hexane, followed by treatment with 1,3-propane diol. These novel stereodefined gem-alkenyldimetallic compounds containing boron and silicon are isolated and characterized by NMR ( 1 H and 13 C) spectral data.