Microwave-assisted selective protection of glutaraldehyde and its symmetrical derivatives as monoacetals and -thioacetals

Enantioselective Aldol Reactions of Aliphatic Aldehydes with Singh’s Catalyst

“…Reaction conditions for self-aldol reactions ( Table 1, Entries 1 -8) were optimized with monoacetal protected glutaraldehyde [28] in a reaction that has been published earlier by us [29]. The aldol reactions presented in this article (Scheme 1) were reproducible and no water elimination was observed.…”

A Scalable, Combined-Batch, and Continuous-Flow Synthesis of a Bio-Inspired UV-B Absorber

“…The transformation of 3,3-dimethylglutaric acid, 15, to the corresponding anhydride 2 is a known reaction that has been reported using either oxalyl chloride in 70 % yield, [13] an 8-fold excess of acetic anhydride in 79 % yield, [14] or an excess of thionyl chloride in 96 % yield. [15] In an attempt to avoid the large excess of acetic anhydride used in the published procedure and the resulting lengthy distillation and recrystallisation, a continuous-flow approach was developed. The performance of synthetic transformations under continuous-flow conditions is an area of intense current interest.…”

Synthesis of (±)‐Lasubine II Using N‐Methoxyamines

“…This widely distributed structure has received considerable attention from the syntheticc hemistst od emonstrate the utility of new methods. Condensation of 5 with aldehyde 6 [9] in the presence of an acid would produce N-oxyiminium ion 7, [10] which would subsequently undergo allylation to afford a-substituted N-methoxyamine 8.T his multi-component reaction could install all carbon atomse mbeddedi nl asubine II (1)i nasingle operation. [6] In this context, we envisioned the synthetic approach to (AE)-lasubine II (1), whosek ey step is the three-component allylation of N-methoxyamine 5 [7,8] (Scheme 1B).…”

“…[6] In this context, we envisioned the synthetic approach to (AE)-lasubine II (1), whosek ey step is the three-component allylation of N-methoxyamine 5 [7,8] (Scheme 1B). Condensation of 5 with aldehyde 6 [9] in the presence of an acid would produce N-oxyiminium ion 7, [10] which would subsequently undergo allylation to afford a-substituted N-methoxyamine 8.T his multi-component reaction could install all carbon atomse mbeddedi nl asubine II (1)i nasingle operation. The key to success is based on the uniquereactivitiesderived from the N-methoxy group.…”