Cu-catalyzed hydroxycyclopropanol ring-opening cyclization to tetrahydrofurans and tetrahydropyrans: short total syntheses of hyperiones

Abstract

A novel Cu-catalyzed hydroxycyclopropanol ring-opening cyclization was developed to synthesize substituted tetrahydrofuran/tetrahydropyran molecules including two norlignan natural products hyperiones A and B.

Visible Light‐Induced Intramolecular C─O Bond Formation via 1,5‐Hydrogen Atom Transfer Strategy

“…J, were reported in hertz unit (Hz). 13 C NMR was recorded on 100 or 150 MHz and was fully decoupled by broad band proton decoupling. Chemical shifts were reported in ppm referenced to the center line of a triplet at 77.0 ppm of CDCl 3 .…”

“…Despite the broad applications of intramolecular C─O bond formation to obtain cyclic ether derivatives, many reactions often require high loading of transition metal catalysts or harsh reaction conditions such as high temperature. [7][8][9][10][11][12][13][14][15][16] In this context, the development of a mild and eco-friendly synthetic method to synthesize cyclic ether derivatives is of great interest.…”

Stereoselective Synthesis of anti-2,4-Disubstituted Tetrahydrofurans via a Pd-Catalyzed Hayashi–Heck Arylation and Rh-Catalyzed Hydroformylation Sequence

“…However, this latter method proved to be more effective for syn-2,5-THFs, putatively due to steric strain in the transition state for the required diastereomeric substrate leading to anti-2,4 THFs (Figure 2C). 8 Given the lack of suitable methods for the construction of the key THF core of GDC-6599 (Figure 1), we sought to develop a concise synthetic sequence amenable to large-scale manufacturing. To accomplish the efficient and stereodefined synthesis of 4a, we envisioned forging the initial stereocenter by Hayashi−Heck arylation 9 of 4-chlorophenol triflate 1a and 2,3-dihydrofuran to afford 5-aryl-2,3-dihydroforun 2a (Scheme 1).…”

“…In another example, Cuerva and co-workers showed that a Ti/Ni/Mn trimetallic system could afford anti -2,4-disubstituted THFs in good diastereoselectivity via a reductive Heck-type cyclization (Figure B). , More recently, Dai and co-workers showed that the Cu-catalyzed cyclopropyl alcohol ring opening could furnish anti -2,4 THFs. However, this latter method proved to be more effective for syn -2,5-THFs, putatively due to steric strain in the transition state for the required diastereomeric substrate leading to anti -2,4 THFs (Figure C) …”

Nickel-Catalyzed Carbonylation of Cyclopropanol with Benzyl Bromide for Multisubstituted Cyclopentenone Synthesis

“…Cyclopropanols, easily accessible compounds with intrinsic strain property, are often regarded as an important class of homoenolate equivalent, which can intercept with various electrophiles to forge different functional groups at the β-position of carbonyl compounds . Pioneered by seminal works developed by Nakamura and Kuwajima using siloxycyclopropanes as the homoenolate precursor to participate in diverse addition and cross-coupling reactions mediated by metal salts, numerous ring-opening cross-coupling reactions of cyclopropanol by transition metals have been devoted to access a variety of functionalities at the β-position of ketone moiety. − The existing protocols mainly focus on the intramolecular cycloisomerization or two-component cross-coupling (Scheme i, a). Despite the sustainable advances, the multicomponent reaction of the cyclopropanol is underdeveloped.…”