Mark A. Wolf

Remarkable increase in the diastereofacial selectivity of the addition of β-methyl α-(alkoxy)allylstannane to aldehydes: substituent effects on diastereofacial selectivity

Several new chiral allylstannanes were prepared and reacted with aldehydes. Excellent diastereofacial selectivity was observed for the reactions of allylstannane 1 with aldehydes in the presence of BF3·Et2O. This is in contrast to the results from other allylstannanes which do not bear a β-methyl group. These observations were rationalized based on a combination of steric and electronic effects.

Conformational preferences of C1-oxygenated acyclic chiral alkenes : the effect of vinyl and allyl substituents

Abstract The conformational preferences of several chiral alkenes have been studied by the variable temperature NMR technique. Electron-withdrawing groups (EWG) enhance the C-O eclipsed form, and electron-releasing groups (ERG) favor the C-H eclipsed form in these C1-oxygenated chiral alkenes.

Evidence for Synclinal Transition State in the Reactions of Aromatic Aldehydes with α-(Alkoxy)allylstannanes

Abstract Unlike aliphatic aldehydes, aromatic aldehydes produce greater than 95% of syn-(Z) enol ether when treated with α-(alkoxy)allylstannanes in the presence of BF3·Et2O. However, in the presence of TiCl4, the reaction of p-chloro-o-methoxybenzaldehyde with α-(alkoxy)crotylstannane produced predominantly the syn-(E) isomer.

X-ray structure of a chiral alkene: direct evidence for CH bond eclipsing C=H bond

Abstract A single crystal X-ray structure determination of the chiral alkene, (1Z)-1-(benzyloxymethyloxy)-3-cyclohexyl-4-phenyl-1-buten-4-ol, ( 1 ), is described. The observed conformation about the C sp2 -C sp3 bond of 1 is the C H eclipsed form in the crystal and in solution. The observed torsional angles in the acetal portion of the structure are −65° for R′-O-C-O and −59° for O-C-O-R″.