Catalytic asymmetric synthesis of 3,4-disubstituted cyclohexadiene carbaldehydes: formal total synthesis of cyclobakuchiols A and C

The first catalytic approach for the asymmetric synthesis of 3,4-disubstituted cyclohexadiene carbaldehydes through an inverse-electron-demand Diels–Alder reaction is described. A variety of arylacetaldehydes and α,β,γ,δ-unsaturated aldehydes are tested under the mild reaction conditions catalyzed by l-proline to obtain the trans diastereomeric products with good yields and high enantioselectivities. The scope of this methodology is further extended to the asymmetric synthesis 3,4-disubstituted cyclohexane carbaldehydes and their derivatives. The practicality of this method is demonstrated by the gram-scale synthesis. This methodology is successfully applied for the formal total synthesis of cyclobakuchiol A, an antipyretic and anti-inflammatory agent, and cyclobakuchiol C.by Vidyasagar Maurya and Chandrakumar Appaye

Stereoselective synthesis of cytotoxic anhydrophytosphingosine pachastrissamine [Jaspine B]

A practical stereoselective synthesis of cytotoxic anhydrophytosphingosine pachastrissamine (jaspine B) was achieved in 48% overall yield from D-(-)-tartaric acid. Key features of the sequence include the diastereoselective formation of a tetrol with three contiguous chiral centers, which was further elaborated to pachastrissamine. The synthetic route is operationally simple, diastereoselective and is amenable for the synthesis of a number of analogues of pachastrissamine

Highly Regio- and Enantioselective functionalization of Linear ?,?-Unsaturated Aldehydes

by Mahesh S. Kutwal and Chandrakumar Appaye

Trifluoroethanol mediated regioselective g-alkylation of linear a,?-unsaturated aldehydes enantioenriched by an in situ kinetic resolution

by Mahesh Kutwal and Chandrakumar Appaye

Nucleophilic addition reactions of 1,4-diketones derived from tartaric acid: Synthesis of TADDOL analogues

A systematic investigation of the reduction and Grignard reagents addition to 1,4-diketones derived from tartaric acid was carried out. It was found that the reduction proceeded with high selectivity using K-Selectride as the reducing agent; while Grignard reagent addition was highly dependent on structure of the dione as well as on the Grignard reagent. The resultant 1,4-diols represent a series of novel TADDOL analogues

Deuterium Studies Reveal a New Mechanism for the Formose Reaction Involving Hydride Shifts

In the formose reaction, formaldehyde is converted to glycolaldehyde, its dimer, under credible prebiotic conditions. Breslow proposed a mechanism for the process in 1959, but recent studies by Benner showed that it was wrong in detail. Our present studies clarify the mechanism, which involves the original Breslow intermediates but some different connecting steps

Short and efficient asymmetric synthesis of (S)-paraconic acid and IM-2 using organocatalysis

by Abhijeet Sarkale and Chandrakumar Appaye