Synlett 2022; 33(06): 581-584
DOI: 10.1055/s-0040-1719904
letter

Total Syntheses of Spirooliganones A and B

Masao Morita
a   Research Foundation ITSUU Laboratory, C1232 Kanagawa Science Park R and D Building, Takatu-ku, Kawasaki 213-0012, Japan
,
Nobuaki Nemoto
b   JEOL RESONANCE Inc., Musashino, Akishima, Tokyo 196-8558, Japan
,
Ken Ohmori
c   Department of Chemistry, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8551, Japan
› Author Affiliations
This work was generously supported by funding from the Research Foundation ITSUU Laboratory.


Abstract

This paper describes the total syntheses of spirooliganones A and B, which provides control over the stereochemistry of the spiro center via a cascade reaction involving the in situ formation of an o-quinone methide and a hetero-Diels–Alder reaction.

Supporting Information



Publication History

Received: 10 December 2021

Accepted after revision: 07 February 2022

Article published online:
08 March 2022

© 2022. Thieme. All rights reserved

Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany

 
  • References and Notes

  • 1 Ma S.-G, Gao R.-M, Li Y.-H, Jiang J.-D, Gong N.-B, Li L, Lü Y, Tang W.-Z, Liu Y.-B, Qu J, Lü H.-N, Li Y, Yu S.-S. Org. Lett. 2013; 15: 4450
  • 2 Wei L, Xiao M, Xie Z. Org. Lett. 2014; 16: 2784
  • 3 Song L, Yao H, Tong R. Org. Lett. 2014; 16: 3740
  • 4 Nan Z, Ren X, Ren J, Lü H, Ma S, Gao R, Li Y, Xu S, Li L, Yu S. Org. Lett. 2015; 17: 3118
  • 7 Tamura Y, Yakura T, Haruta J, Kita Y. J. Org. Chem. 1987; 52: 3927
  • 10 Potassium triethylborohydride (0.194 mL, 1.0 M THF solution, 0.194 mmol) was added to a solution of 9 (50.0 mg, 0.129 mmol) in THF/HMPA (5:1, 2 mL) at –78 °C. After 15 min of stirring at –78 °C, saturated aqueous NH4Cl was added to the reaction mixture, and the mixture was extracted with EtOAc (3×). The combined organic extracts were dried (MgSO4) and concentrated in vacuo. The residue was purified by PTLC (hexane/EtOAc = 7:1) to afford 8 (22.5 mg, 47%) as a white solid and 16 (5.3 mg, 11%) as a white solid.Compound 8: Rf = 0.63 (hexane/EtOAc = 7:1); [α]D 23 –29 (c 1.2, CHCl3). IR (neat): 2944, 1685, 1123, 881 cm–1. 1H NMR (400 MHz, CDCl3): δ = 1.07–1.14 (m, 21 H), 1.35 (s, 3 H), 1.37 (s, 3 H), 2.15 (dd, J = 13.5, 4.3 Hz, 1 H), 2.72 (dd, J = 13.5, 5.5 Hz, 1 H), 4.40 (t, J = 4.8 Hz, 1 H), 5.85 (dd, J = 13.3, 1.6 Hz, 1 H), 6.03 (d, J = 9.8 Hz, 1 H), 6.97 (t, J = 10.3 Hz, 1 H). 13C NMR (100 MHz, CDCl3): δ = 10.2, 15.96, 15.99, 21.7, 25.4, 41.0, 74.2 (d, J CF = 23.1 Hz), 77.0, 85.2, 106.8 (d, J CF = 11.6 Hz), 123.3, 146.0 (d, J CF = 4.8 Hz), 172.6 (d, J CF = 290.9 Hz), 185.2 (d, J CF = 16.4 Hz). 19F NMR (376 MHz, CDCl3): δ = –98.4. HRMS (ESI): m/z calcd for C20H34O3FSi [M + H]+: 369.2256; found: 369.2242.Compound 16: Rf = 0.57 (hexane/EtOAc = 7:1). [α]D 23 –9.3 (c 0.57, CHCl3). IR (neat): 2944, 1683, 1139, 883 cm–1. 1H NMR (400 MHz, CDCl3): δ = 1.07–1.12 (m, 21 H), 1.30 (d, J = 0.9 Hz, 3 H), 1.40 (s, 3 H), 2.26 (dd, J = 12.9, 7.0 Hz, 1 H), 2.58 (dd, J = 12.6, 9.6 Hz, 1 H), 4.38 (dd, J = 9.5, 6.7 Hz, 1 H), 5.87 (dd, J = 13.0, 1.6 Hz, 1 H), 6.03 (dt, J = 9.8, 1.3 Hz, 1 H), 6.62 (t, J = 10.2 Hz, 1 H). 13C NMR (100 MHz, CDCl3): δ = 12.2, 17.9, 18.0, 22.4 (d, J CF = 2.9 Hz), 28.4, 41.2, 74.3 (d, J CF = 24.1 Hz), 78.2, 85.2, 109.3 (d, J CF = 11.6 Hz), 125.5, 146.7 (d, J CF = 4.8 Hz), 174.0 (d, J CF = 291.9 Hz), 187.1 (d, J CF = 15.4 Hz). 19F NMR (376 MHz, CDCl3): δ = –96.6. HRMS (ESI): m/z calcd for C20H34O3FSi [M + H]+: 369.2256; found: 369.2247.
  • 12 For the in situ generation of o-quinone methide 6 in a sealed tube, see ref. 2.
  • 13 The diastereomeric mixture of adduct 17 and 18 was separated by recycling HPLC (LC-Forte/R equipped with YMC-Pack SIL-60, hexane/EtOAc = 9:1, 25 mL/min).
  • 14 Johnson CR, Adams JP, Braun MP, Senanayake CB. W, Wovkulich PM, Uskoković MR. Tetrahedron Lett. 1992; 33: 917