Kailash P. Pawar

Enantioselective syntheses of (R)-pipecolic acid, (2R,3R)-3-hydroxypipecolic acid, β-(+)-conhydrine and (−)-swainsonine using an aziridine derived common chiral synthon

Concise total syntheses of (R)-pipecolic acid, (R)-ethyl-6-oxopipecolate, (2R,3R)-3-hydroxypipecolic acid and formal syntheses of β-(+)-conhydrine, (−)-lentiginosine, (−)-swainsonine and 1,2-di-epi-swainsonine have been accomplished starting from a common chiral synthon. The present strategy employs regioselective aziridine ring opening, Wittig olefination and RCM as the key chemical transformations.

A novel, concise and efficient protocol for non-natural piperidine compounds

Formal synthesis of L-altro-1-deoxynojirimycin, cis-3-hydroxypipecolic acid along with synthesis of (R)-piperidinol and a conceptually different advanced intermediate for non-natural piperidine alkaloids is reported from cis-butene-1,4-diol. The key reactions involved are Johnson–Claisen rearrangement, Sharpless asymmetric dihydroxylation, reductive lactamization and novel regioselective elimination.

Total syntheses of D-allo-1-deoxynojirimycin and L-talo-1-deoxynojirimycin via reductive cyclization

Synthesis of a polyhydroxypiperidine framework for L-talo-1-deoxynojirimycin and D-allo-1-deoxynojirimycin was achieved from L-tartaric acid by employing flash dihydroxylation and reductive lactamisation as the key steps.

A protecting group free and scalable approach towards total synthesis of (−)-venlafaxine

A protecting group free asymmetric total synthesis of (−)-venlafaxine is reported. The strategy employs Sharpless epoxidation and regio-selective epoxide ring opening by an in situ generated Gilman reagent as key steps. This paper reports a 53% overall yield in 6 steps for total synthesis of (−)-venlafaxine.