Synthesis of depressin, cryptomeridiol and 4-epi-cryptomeridiol enabled by a terpenoid chiral pool-producing platform

• Yao Kong,
• Tao Wang,
• Chen Wang,
• Pengcheng Zhang,
• Yuanning Liu,
• Kaibiao Wang,
• Fen Liu,
• Hongli Jia and
• Zhengren Xu

Beilstein J. Org. Chem. 2026, 22, 683–690, doi:10.3762/bjoc.22.53

• hydroxy group allowed the synthesis of compound 1 from 4 in nine steps. Selective acid-mediated 5,10-transannular cyclization of 5 followed by hydration reaction furnished both products 2 and 3 in two steps. Keywords: chemoenzymatic synthesis; chiral pool; isopentenol utilization pathway; terpene

• 3, respectively, in a more efficient and selective way by protein engineering, we thought that germacrene A (5), whose terpene cyclases are widely found in different organisms [52], could serve as a precursor for synthesis of both 2 and 3 via a transannular cyclization process [37][53][54]. A

• relatively far apart from each other, and we have not isolated any products resulting from transannular cyclization of the double bonds during the conditions screening for allylic oxidation. With enone 9 in hands, both C9 and C5 position could be hydroxylated by using the same SeO2-mediated allylic oxidation

Recent advances in controllable/divergent synthesis

• Jilei Cao,
• Leiyang Bai and
• Xuefeng Jiang

Beilstein J. Org. Chem. 2025, 21, 890–914, doi:10.3762/bjoc.21.73

• –acceptor BCB via Sc(OTf)3 coordination to its carbonyl group facilitates nucleophilic attack by vinylazide 33, forming an imino-diazonium intermediate Int-40 accompanied by a δ-carbanion. Transannular cyclization of this species affords 2-azidobicyclo[3.1.1]hexane (2-azidoBCHs). Subsequent thermal

From dipivaloylketene to tetraoxaadamantanes

• Gert Kollenz and
• Curt Wentrup

Beilstein J. Org. Chem. 2018, 14, 1–10, doi:10.3762/bjoc.14.1

• bisdioxine and tetraoxaadamantane formation are discussed. Keywords: bisdioxines; dipivaloylketene; tetraoxaadamantanes; transannular cyclization; Introduction The tetraoxaadamantane ring system is relatively unknown and no functional group derivatives had been reported prior to our work. The first methyl

• unusual reaction steps: (i) the conversion of the dimer 3 of dipivaloylketene (2) to bisdioxines (2,6,9-trioxabicyclo[3.3.1]nona-3,7-dienes) 4, by the addition of nucleophiles, and (ii) the facile acid-catalyzed hydrolysis of 4 with concomitant transannular cyclization. Following this route a wide variety

Enantioselective synthesis of polyhydroxyindolizidinone and quinolizidinone derivatives from a common precursor

• Nemai Saha and
• Shital K. Chattopadhyay

Beilstein J. Org. Chem. 2014, 10, 3104–3110, doi:10.3762/bjoc.10.327

• [29], ring expansion–transannular cyclization [30], Cope–House cyclization [31], etc. as key steps. Although great advances have been made, creation of diverse entities from a single source remains important. Herein, we report a synthetic entry to some polyhydroxylated indolizidine and quinolizidine

Scalable synthesis of 5,11-diethynylated indeno[1,2-b]fluorene-6,12-diones and exploration of their solid state packing

• Bradley D. Rose,
• Peter J. Santa Maria,
• Aaron G. Fix,
• Chris L. Vonnegut,
• Lev N. Zakharov,
• Sean R. Parkin and
• Michael M. Haley

Beilstein J. Org. Chem. 2014, 10, 2122–2130, doi:10.3762/bjoc.10.219

• transannular cyclization of 10 using elemental iodine under air [21]. Dehydrobenzo[12]annulene 10 in turn was synthesized via Glaser homocoupling of 1,2-diethynylbenzene [21][22][23]. While in theory this route permitted relatively easy access to diethynyldiones 8, in practice it was fraught with problems: (1

• . Black lines represent the molecules with circles denoting the centroid. Transannular cyclization route to diethynyl-IF-diones 8. Suzuki/Friedel-Crafts route to diethynyl-IF-diones 8. Diethynyl-IF-diones synthesized and yields for Sonogashira cross-coupling. Electrochemical and optical data for ID-diones