J. Seyden-Penne

Stereoselective synthesis of cis or trans N-phenyl 2-phenyl decahydroquinolin-4 ones by catalyzed hetero-Diels-Alder reaction.

Cis or trans N-phenyl 2-phenyl decahydroquinolin-4 ones can be synthesized highly selectively.

Reformatsky Reaction Using Zn/Ag Couple

Abstract The Reformatsky reaction is easy to run in ethereal solvents in the presence of Zn/Ag couple. From methyl γ-bromocrotonate and ketones, ramified esters are formed in refluxing Et20, linear ones in refluxing THF.

Aminonitrile and cyanohydrin ethers as benzoyl anion equivalents in conjugate additions to substituted α cyclenones : comparative synthetic potentialities

Abstract Lithiated aminonitrile 1a and cyanohydrin ether 2a are good nucleophilic benzoyl equivalents in conjugate addition to α cyclenones. 1a is more sensitive to β substitution of the cyclenone than 2a , as in THF it does not react with 3-methyl substituted cyclohexenones 6a , b . From 2-methyl and 2-fluorocyclenones and 1a or 2a , cis 2-subsyituted 3-benzoylcyclanones are stereoselectively obtained, provided that mild unmasking conditions were used. The intermediate enolates trapping, leading to trans 2-substituted 3-benzoylcyclanones, is discussed, according to the nucleophilic reagent and the alkylating agent nature. A comparison with silyl ether cyanohydrin 2b shows the broader synthetic usefulness of 1a and 2a .

Substituent effects on 1–2 versus 1–4 addition of lithiated arylacetonitriles to 2-cyclohexenones in tetrahydrofuran

Abstract The reaction of organolithium derivates with α β unsaturated ketones gives, generally, allylic alcohols resulting from 1–2 addition (1). Recently, it has been shown that 1–4 addition products can be obtained in diethyl ether or in tetrahydrofuran (THF) either under kinetic control (2), mainly when the carbonyl group is sterically hindered (3,4), or under thermodynamic control when the lithiated reagent is substituted by electron delocalizing groups (5–16).

Competition between allylic substitution and michael addition with carbanions ∝ to nitriles.

Abstract The reaction of methyl 4-bromo-4-methylcrotonate 1 with anionic species ∝- to nitriles does not lead to cyclopropanes via a MIRC process. Products originating from a SN′ reaction, 3 and 6 , are predominantly formed from 2a-c , while products resulting from SN and SN′ reactions are obtained in equimolar amounts from aminonitrile 2d .

Conjugate Addition In Phase Transfer Catalysis Conditions: Reactions of α Enones with Arylacetonitriles

Abstract Conjugate addition of arylacetonitriles 1–3 to α-enones 4–6 can be performed in liquid-liquid PTC conditions (toluene-saturated aqueous K3CO3 solution). The reaction is too slow with isophorone or mesityloxide to be synthetically useful.

Effect of aggregation of nitrile anions on the 1,2 versus 1,4 regioselectivity towards benzylideneacetone

Abstract A direct evidence of the influence of aggregation state of lithiated phenylacetonitrile 1 on the 1,2 versus 1,4 regioselectivity towards benzylideneacetone 2 was established. Progressive addition of hexane to THF solutions raised the aggregates proportion of 1 as evidenced by IR νCN band and led to an increase of 1,4 adduct. Monomers afforded 1,2 addition in pure THF.

Diastereo- and enantioselective allylic SN′ substitution by phenylacetic esters enolates.

Abstract The Anti-Michael S N′ substitution of γ-bromo-α,β-unsaturated esters 1a-c by Li t.butyl phenylacetate enolate is highly diastereoselective. Asymmetric synthesis can be performed (ee > 95%) using the enantiomerically pure (1′R,2′S) 2-phenyl cyclohexyl ester 1c .

Poster: “Lewis acid catalyzed Hetero Diets Alder Reactions”

The cycloaddition of phenylimines PhCH=NR to enoxysilane 1 takes place under Lewis acid catalysis, leading to two cycloadducts in ratios which depend upon the nature of the nitrogen substituent, the Lewis acid and the reaction conditions. Their protonation by MeOH/Et3N gives diastereoisomeric decahydroquinolinones also in various ratios.