A wide‐ranging study of Suzuki reactions which use nitrogen‐containing heterocycles is described (see scheme; dba=dibenzylideneacetone, Cy=cyclohexyl). This method is highly versatile (a single procedure was used for all substrates, including boronate esters and trifluoroborates), compatible with a variety of unprotected functionalities (e.g., NH2‐ and OH‐substituted substrates), and efficient even with unactivated aryl chlorides.

Eine umfassende Studie zu Suzuki‐Reaktionen mit Stickstoffheterocyclen wird vorgestellt (siehe Schema; dba=Dibenzylidenaceton, Cy=Cyclohexyl). Die Methode ist vielseitig (ein einziges Verfahren für alle Substrate einschließlich Boronatester und Trifluorborate), auf Substrate mit ungeschützten funktionellen Gruppen (NH2 und OH) anwendbar und auch für nichtaktivierte Arylchloride geeignet.

[reaction: see text] beta-Ketoesters can be effectively monofluorinated with F-TEDA using CpTiCl(3) as a catalyst. With the use of this catalyst, the extent of the competing difluorination does not reach 10%. [TiCl(2)(TADDOLato)] complexes catalyze the one-pot enantioselective heterodihalogenation of beta-ketoesters with F-TEDA and NCS to afford alpha-chloro-alpha-fluoro-beta-ketoesters in moderate to good yields. The sequence of addition of the halogenating agents determines the sense of chiral induction.

The substrate range of the [TiCl2(TADDOLate)] (TADDOL=α,α,α′,α′‐tetraaryl‐1,3‐dioxolane‐4,5‐dimethanol)‐catalyzed asymmetric α‐fluorination of activated β‐carbonyl compounds has been investigated. Optimal conditions for catalysis are characterized by using 5 mol‐% of TiCl2(naphthalen‐1‐yl)‐TADDOLate) as catalyst in a saturated (0.14 mol/l) MeCN solution of F‐TEDA (1‐(chloromethyl)‐4‐fluoro‐1,4‐diazoniabicyclo[2.2.2]octane bis‐[tetrafluoroborate]) at room temperature. A series of α‐methylated β‐keto esters (3‐oxobutanoates, 3‐oxopentanoates) with bulky benzyl ester groups (60–90% ee) or phenyl ester (67–88% ee) have been fluorinated readily, whereas α‐acyl lactones were also readily fluorinated, but gave lower inductions (13–46% ee). Double stereochemical differentiation in β‐keto esters with chiral ester groups raised the stereoselectivity to a diastereomeric ratio (dr) of up to 96.5 : 3.5. For the first time, β‐keto S‐thioesters were asymmetrically fluorinated (62–91.5% ee) and chlorinated (83% ee). Lower inductions were observed in fluorinations of 1,3‐diketones (up to 40% ee) and β‐keto amides (up to 59% ee). General strategies for preparing activated β‐carbonyl compounds as important model substrates for asymmetric catalytic α‐functionalizations are presented (>60 examples).

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