A reductive coupling strategy towards ripostatin A

• Kristin D. Schleicher and
• Timothy F. Jamison

Beilstein J. Org. Chem. 2013, 9, 1533–1550, doi:10.3762/bjoc.9.175

• diastereoselectivity around 10:1, with further enhancement following silyl protection and purification. Although the silylated compound 60 proved to be reluctant to form the Weinreb amide, microwave irradiation allowed this process to proceed on a reasonable time scale. Grignard addition to the Weinreb amide afforded

Efficient synthesis of β’-amino-α,β-unsaturated ketones

• Isabelle Abrunhosa-Thomas,
• Aurélie Plas,
• Nishanth Kandepedu,
• Pierre Chalard and
• Yves Troin

Beilstein J. Org. Chem. 2013, 9, 486–495, doi:10.3762/bjoc.9.52

• ester moiety to a Weinreb amide [18] followed by changing the nitrogen protecting group to a carbamate furnished the key intermediate 6, which could be further alkylated with Grignard reagents to give β’-amino protected α,β-enone 1 in good overall yield and high enantiomeric excess. As Grignard reagents

Inter- and intramolecular enantioselective carbolithiation reactions

• Asier Gómez-SanJuan,
• Nuria Sotomayor and
• Esther Lete

Beilstein J. Org. Chem. 2013, 9, 313–322, doi:10.3762/bjoc.9.36

• diastereoselectivity and the enantioselectivity. As shown on Scheme 19, the best results in terms of enantioselectivity were obtained by using Weinreb amide 51c, though with moderate diastereoselectivity. Conclusion As has been shown through these examples, the enantioselective carbolithiation reaction is an

Asymmetric synthesis of quaternary aryl amino acid derivatives via a three-component aryne coupling reaction

• Elizabeth P. Jones,
• Peter Jones,
• Andrew J. P. White and
• Anthony G. M. Barrett

Beilstein J. Org. Chem. 2011, 7, 1570–1576, doi:10.3762/bjoc.7.185

• high diastereoselectivity, but in more modest yields. Acylation with acetyl chloride (Table 1, entry 7) afforded ketone 6g in 59% yield, with a lower dr of 89:11, most likely due to the less sterically hindered nature of this electrophile. Replacing acetyl chloride with its corresponding Weinreb amide

Metathesis access to monocyclic iminocyclitol-based therapeutic agents

• Ileana Dragutan,
• Valerian Dragutan,
• Carmen Mitan,
• Hermanus C.M. Vosloo,
• Lionel Delaude and
• Albert Demonceau

Beilstein J. Org. Chem. 2011, 7, 699–716, doi:10.3762/bjoc.7.81

• produce the (+)-DMDP (49) and (−)-bulgecinine (50) (Scheme 8). The starting point in the synthesis of (+)-broussonetine G, 53, was the same annulated oxazolone 48 which, after conversion into the Weinreb amide 51, was coupled with the alkyl bromide substituted spiro compound 52 (Scheme 9). In fact, the

Synthesis and enzymatic evaluation of 2- and 4-aminothiazole- based inhibitors of neuronal nitric oxide synthase

• Graham R. Lawton,
• Haitao Ji,
• Pavel Martásek,
• Linda J. Roman and
• Richard B. Silverman

Beilstein J. Org. Chem. 2009, 5, No. 28, doi:10.3762/bjoc.5.28

• the Weinreb amide. Reduction with LAH gave aldehyde 22 (Scheme 3). Compounds 17 and 22 were condensed to form an imine prior to the addition of NaHB(OAc)3, giving secondary amine 23. Removal of the Boc groups with acid gave 3 as a tetrahydrochloride salt. The 4-aminothiazoles were constructed as shown