The nBu(3)SnH-mediated cyclisation reactions of allylic-allylic alkylation products of alpha,alpha-dicyanoalkenes and Morita-Baylis-Hillman (MBH) carbonates of methyl vinyl ketone (MVK) have been investigated. Cyclopentane derivatives bearing multiple substituents were efficiently prepared with moderate to excellent diastereoselectivity.

Department of Chemistry, 1102 Natural Sc California 92697-2025, USA. E-mail: leoverm Department of Molecular Medicine, Bec Comprehensive Cancer Center, 1500 E. D USA. E-mail: [email protected] † Electronic supplementary information (E and diastereoselectivity in the synthesis of procedures, and characterization data 1061869–1061873. For ESI and crystallog format see DOI: 10.1039/c5sc01536g Cite th...

[Reaction: see text] Various substituted conjugated dienes have been made by olefin cross-metathesis. Using either electronic or steric "protection," one of the olefins of the conjugated diene was deactivated relative to the other for cross-metathesis. The reactions proceed with very high chemoselectivity and, when steric deactivation is used, very high diastereoselectivity.

The Reformatsky reaction of ethyl bromodifluoroacetate to α-oxygenated sulfinylimines is described. Using Honda-Reformatsky conditions, the reaction proceeds with double diastereodifferentiation, with the configuration of the sulfinyl group determining the stereochemical course of the reaction. Excellent diastereoselectivities (>94:6) are obtained for the matched cases. In contrast, reaction wi...

A one-pot nickel-catalyzed allylation of aromatic aldehydes with α-halo-β,β-difluoropropene-containing compounds promoted by ZnEt(2) under mild conditions was described. The reaction displays moderate to good regio- and diastereoselectivity, tolerates a wide range of functional groups, and provides an efficient method for the synthesis of γ-fluorinated homoallylic alcohols.

A synthesis of the ABC tricyclic ring system of the clionastatins, an unusual pair of highly chlorinated androstane steroids, has been accomplished. This work provides strong support for the original structural proposal. An unexpected substrate-dependent reversal in alkene chlorination diastereoselectivity was critical to success. This approach should be amenable to an eventual enantioselective...

Chiral aminoalkyl epoxyaziridine 1 is synthesized in high yield and diastereoselectivity from L-serine. Ring opening of epoxyaziridine 1 with primary amines is carried out with total chemo- and regioselectivity, affording chiral polyfunctionalized piperidines 8. The structure of these trisubstituted piperidines is established by NMR studies.

An interesting sequential reaction involving Sonogashira coupling, propargyl-allenyl isomerization, intramolecular [4 + 2] cycloaddition, and bridged oxa-ring opening has been realized, providing a facile method for the synthesis of functionalized dihydroisobenzofurans from easily accessible starting materials with a decent diastereoselectivity.

Diastereoselectivity in reactions of aryl-stabilised ammonium ylides are highly sensitive to the nature of the amine and the ylide substituent. DFT calculations are consistent with a mechanism in which reversibility in betaine formation [despite the high energy (and therefore instability) of ammonium ylides] is finely balanced due to the high barrier to ring closure.