含硼的弱路易斯酸首次被证明是酮加氢成醇时的沮丧路易斯对(FLP)催化剂的活性组分。将有机超强碱(pyrr)3 P = N t Bu与路易斯酸9-(4-CF 3 - C 6 H 4)-BBN结合产生一种“逆向” FLP催化剂,该催化剂能够加氢包括N在内的一系列脂族和芳族酮,O和S功能化的底物以及生物质衍生的乙酰丙酸乙酯。初步的计算和实验研究表明,使用“逆” FLP进行催化氢化的机理不同于包含强路易斯酸(例如B(C 6 F 5))的常规FLP催化剂。)3。
Multicomponent Mannich Reactions with Boron Enolates Derived from Diazo Esters and 9-BBN
作者:Yi Luan、Scott E. Schaus
DOI:10.1021/ol200766t
日期:2011.5.6
3-component Mannich condensation reaction. Catalyzed by Cu(II) salts, the reaction affords the corresponding isocyanate Mannich product: one that can be easily trapped in situ by other nucleophiles. The Mannich condensation corresponds to an α,α-disubstituted enolate addition to imines. The reaction was rendered asymmetric by using the (−)-phenylmenthol ester in good yield and selectivities.
Combining Enantioselective Rh‐Catalyzed Conjugate Addition and Ir‐Catalyzed Allylic Alkylation in Stereodivergent, Multicomponent Coupling Reactions to Form Three Stereocenters
作者:Qiqige Qiqige、Rylan J. Lundgren、Duanyang Kong
DOI:10.1002/chem.202300727
日期:——
The stereodivergent three-component coupling of enones, aryl boron nucleophiles and allyl carbonates can be achieved with a combination of Rh- and Ir-based catalysts. Products containing three contiguous stereocenters can be prepared with >95 % ee and >90 : 10 dr.
烯酮、芳基硼亲核试剂和碳酸烯丙酯的立体发散三组分偶联可以通过Rh基和Ir基催化剂的组合来实现。含有三个连续立构中心的产品可以使用 >95 % ee 和 >90 : 10 dr 来制备。
Stereoselective Suzuki Coupling Reaction of an α-Bromo-α-fluoro-β-lactam
A new strategy has been developed for the synthesis of alpha-aryl-alpha-fluoro-beta-lactams via the Suzuki cross-coupling of alpha-bromo-alpha-fluoro-beta-lactam with a range of different aryl-(9-BBN) reagents. This method provides facile access to multisubstituted alpha-fluoro-beta-lactams in a diastereoselective manner. The synthetic utility of alpha-bromo-alpha-fluoro-beta-lactam has been demonstrated by the arylation of alpha-bromo-alpha-fluoro-beta-lactam.
Generation of Chiral Boron Enolates by Rhodium-Catalyzed Asymmetric 1,4-Addition of 9-Aryl-9-borabicyclo[3.3.1]nonanes (<i>B</i>-Ar-9BBN) to α,β-Unsaturated Ketones
Asymmetric 1,4-addition of 9-phenyl-9-borabicyclo[3.3.1]nonane (2m) to 2-cyclohexenone (1a) proceeded with high enantioselectivity in toluene at 80 degreesC in the presence of 3 mol % of a rhodium catalyst generated from [Rh(OMe)(cod)](2) and (S)-binap to give a high yield of boron enolate (S)-3am, which is 98% enantiomerically pure. Reaction of the boron enolate 3am with electrophiles, methanol-d, propanal, and allyl bromide, gave the corresponding 2-substituted (3S)-3-phenylcyclohexanones with perfect regio- and diastereoselectivity.