Enantiomerically-enriched alkoxy stannanes such as 3 are versatile intermediates for synthesis. John R. Falck of UT Southwestern found (Angew. Chem. Int. Ed. 2008, 47, 6586) that the simple combination of Bu3 SnH and Et2Zn generated a reagent that added to aldehydes such as 1 under catalysis by the MIB amino alcohol introduced by Nugent (Chem. Commun. 1999, 1369) to give the adduct 3 in high ee. Gonzalo Blay and José R. Pedro of the Universitat de València showed (Chem. Commun. 2008, 4840) that it was possible to modulate the reactivity of the acidic 4, allowing catalyzed formation of the high ee adduct 5 to dominate. Xiaoming Feng of Sichuan University developed (J. Am. Chem. Soc. 2008, 130, 15770) a Ni catalyst for the intermolecular ene reaction of 6 with 7 to give 8 in high ee. Enantioselective allylation is a key transformation in current organic synthesis. Yoshito Kishi of Harvard University optimized (Organic Lett. 2008, 10, 3073) enantioselective Cr-mediated allylation, with a ligand that can be easily recovered and recycled. Michael J. Krische of UT Austin devised (J. Am. Chem. Soc. 2008, 130, 14891) a ligand-catalyst combination for effecting the enantioselective allylation of alcohols such as 12 . Brian M. Stoltz of Caltech developed (Angew. Chem. Int. Ed. 2008, 47, 6873) a protocol for the enantioselective allylation of the enol ether 15, leading to the construction of oxygenated quaternary centers. Adducts such as 11 and 17 are of interest, inter alia , as direct precursors, by elimination, of the corresponding alkynes. Simon Blakey of Emory University designed (Angew. Chem. Int. Ed. 2008, 47, 6825) a Ru catalyst that mediated enantioselective intramolecular C-H amination, converting the simple alcohol derivative 18 into the versatile secondary amine 19 in high ee. We established (J. Org. Chem. 2008, 73, 9334) a procedure, based on diazo transfer followed by Rh-mediated intermolecular N-H insertion, for aminating menthyl esters and separating the product diastereomers. The menthyl group, easily removed (TFA) from 21, served as a useful reporter of ee, by 1H NMR of the upfield methyl doublets. Wolfgang Kroutil of the University of Graz found (Adv. Synth. Cat. 2008, 350, 2761) that ω-transaminases could effect the reductive amination of methyl ketones such as 22 in high ee.
Correction to “Oxazaborolidinium Ion-Catalyzed Cyclopropanation of α-Substituted Acroleins: Enantioselective Synthesis of Cyclopropanes Bearing Two Chiral Quaternary Centers”
