Unprecedented nucleophile-promoted 1,7-S or Se shift reactions under Pummerer reaction conditions of 4-alkenyl-3-sulfinylmethylpyrroles

• Takashi Go,
• Akane Morimatsu,
• Hiroaki Wasada,
• Genzoh Tanabe,
• Osamu Muraoka,
• Yoshiharu Sawada and
• Mitsuhiro Yoshimatsu

Beilstein J. Org. Chem. 2018, 14, 2722–2729, doi:10.3762/bjoc.14.250

• (diols). Seleno-Pummerer reactions of 3-selanylmethylpyrroles also proceeded via in situ generation of selenoxides, followed by a treatment with TBAH. Keywords: hydroamination; Pummerer reaction; pyrrole; pyrroloazepine; 1,7-sulfur shift; Introduction Pyrrolo- and indoloazepine skeletons are chemical

• stepwise procedure succeeded to give 7-phenylselenodiol 10a in 91% yield. Next, we performed the Pummerer reaction of N-β-methallyl sulfoxide 5b in order to clarify the substituent effects on the N-alkenyl groups. Surprisingly, the reaction of 5b afforded the intramolecular cyclised pyrroloazepine 11b. The

• N-methallylselenopyrrole 6b also gave the pyrroloazepine 10b, which was formed via the 1,7-Se shift reaction. While N-3-methylbut-2-enyl derivatives 4c and 6c yielded 1,7-S- and Se-shifted diols 9c and 10c, respectively. Interestingly, the reaction of N-cinnamylpyrroles 4d and 6d exclusively

Synthesis of densely functionalized enantiopure indolizidines by ring- closing metathesis (RCM) of hydroxylamines from carbohydrate- derived nitrones

• Marco Bonanni,
• Marco Marradi,
• Francesca Cardona,
• Stefano Cicchi and
• Andrea Goti

Beilstein J. Org. Chem. 2007, 3, No. 44, doi:10.1186/1860-5397-3-44

• hydroxy groups gave novel highly functionalized indolizidines. The synthesis of a pyrroloazepine analogue is also described. Conclusion We have developed a new straightforward methodology for the synthesis of densely functionalized indolizidines and pyrroloazepine analogues in 6 steps and 30–60% overall

• straightforward access to indolizidine derivatives and a pyrroloazepine analogue through a key ring closing metathesis (RCM) of sugar derived hydroxylamines 1 and 3 bearing suitable unsaturated substituents at the α and α' positions. Results and discussion Unsymetrically α,α'-disubstituted hydroxylamines 5 and 6

• pyridine at room temperature (Scheme 4). The structure of protected indolizidines 18–19 and of pyrroloazepine 20 (and therefore of compounds 12–14) was unambiguously determined by spectral data, including 2D COSY and 1D NOESY experiments (See Experimental). Final deprotection of 18–20 with an acidic