168007-63-4Relevant academic research and scientific papers
Methyl 2,3,4-Tri-O-benzyl-α-D-glucopyranosyl-derived γ-silyloxy allylic stannanes as reagents for SE2′ additions to aldehydes
Marshall, James A.,Elliott, L. Michelle
, p. 4611 - 4616 (2007/10/03)
The methyl α-D-glucopyranoside allylic stannanes 3.1 and 3.2 were prepared from the 3-(5-pyranosyl)-2-propenal 2.1 and the cuprate Bu3Sn(Bu)CuCNLi2, followed by trapping of the derived enolate with TBSCl. The major stannane, 3.1, underwent BF3-promoted addition to 2-nonynal to afford a single syn adduct 4.1 in 70-90% yield. The minor stannane, 3.2, gave rise to a 70:30 mixture of adduct 4.1 and the diastereomeric syn adduct 5.1 under these conditions. The stereochemistry of the adduct 4.1 was proven by degradation of the bis-TES derivative 4.2 to aldehyde 4.3, prepared independently from the (R,Z)-γ-OTBS crotyl stannane 4.4 and 2-nonynal along similar lines. Analogous degradation of the adducts 4.1 and 5.1 led to a ca. 65:35 mixture of aldehydes 4.3 and its enantiomer. Accordingly, it can be surmised that the addition of stannane 3.2 to 2-nonynal takes place mainly by a syn SE2′ pathway. BF3-promoted additions to enal 6.1 proceeded as expected. Stannane 3.1 afforded the syn adduct 6.2 in 87-97% yield, and stannane 3.2 gave rise to a 9:1 mixture of syn and anti adducts 7.1 and 7.4 in 70-80% yield.
