Enantioselective Synthesis of Benzyl tert‐Butyl Sulfoxides

Abstract

Kehrt, marsch! Ein von einer Aminosäure abgeleiteter Alkohol und ein Arylamid wurden zu einem Kehrenbaustein für Peptidkonformationen kombiniert. Cyclopropananaloga von Tetra‐ und Hexapeptiden bilden parallele Faltblattstrukturen, die durch CH⋅⋅⋅O‐Wasserstoffbrücken stabilisiert werden (siehe Schema). NMR‐spektroskopische Studien bestätigen das Vorliegen von Wasserstoffbrücken.

DMAP‐Catalysed Sulfinylation of Diacetone‐D‐Glucose: Improved Method for the Synthesis of Enantiopure tert‐Butyl Sulfoxides and tert‐Butanesulfinamides

“…Compound 12 S S is an excellent intermediate for the synthesis of diastereomerically pure axially chiral biaryl compounds by Pd‐catalysed Suzuki–Miyaura cross‐coupling 17. In the same way, the reaction of a benzyl Grignard reagent with ( R S )‐diacetone‐ D ‐glucose tert ‐butanesulfinate led to benzyl tert ‐butyl sulfoxide ( 13 S S )36 with no loss in enantiopurity, as shown by HPLC analysis.…”

Stereoselective Synthesis of Lignans of Three Structural Types from a Common Intermediate, Enantioselective Synthesis of (+)‐Yangambin

“…asymmetric oxidation of the disulfide) [25] to the resulting benzyllithium (Scheme 3). [21] The one-pot reaction that involved deprotonation of sulfoxide 5 and addition of enone 6 in THF at -78°C, and then trapping of the resulting enolate with gaseous formaldehyde, assembled key intermediate 4, with excellent diastereoselectivity, and in 72 % yield. Though traces of diastereomeric products may have been formed, none could be isolated by chromatography.…”

“…[21] We now report an enantioselective total synthesis of yangambin by using the sulfoxide-based strategy, which should be applicable both to symmetrical and unsymmetrical furofuran lignans. [21] We now report an enantioselective total synthesis of yangambin by using the sulfoxide-based strategy, which should be applicable both to symmetrical and unsymmetrical furofuran lignans.…”

“…developed an enantioselective synthesis of the benzyl tertbutyl sulfoxides needed as precursors for enantioselective synthesis of lignans. [21] We now report an enantioselective total synthesis of yangambin by using the sulfoxide-based strategy, which should be applicable both to symmetrical and unsymmetrical furofuran lignans. In the course of this work representative members of other families of lignans (2 and 3) were also prepared, which emphasises the versatility of this emerging strategy.…”

Synthetic studies on optically active furofuran and diarylbutane lignans*

“…), needed for the key one-pot reaction, was prepared by the addition of (3,4,5-trimethoxybenzyl)lithium to (R)-29 [40] (>90% e.e.) under the superbasic conditions [41] using n-BuLi, KOt-Bu and 2,2,6,6-tetramethylpiperidine (TMPH) in 47% yield. Deprotonation of sulfoxide 30 with LDA and addition of enone 31 in THF at -78 °C, and trapping of the resultant enolate with formaldehyde afforded 32 (90% e.e.)…”