Lithium–Boron Chemistry: A Synergistic Strategy in Modern Synthesis

Watson, Charlotte G.; Unsworth, Phillip J.; Leonori, Daniele; Aggarwal, Varinder K.

doi:10.1002/9783527667512.ch14

Cited by 14 publications

(8 citation statements)

References 43 publications

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“…[65] This stereospecific arylation protocol is based on the Zweifel olefination reaction (Scheme 20), but now extended to electron-rich aromatics. [40,66] Because there is no transmetalation step, unfunctionalized secondary and tertiary boronic esters can be used.…”

Section: Methodsmentioning

confidence: 99%

Stereospecific Couplings of Secondary and Tertiary Boronic Esters

2014

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Section: Methodsmentioning

confidence: 99%

Stereospecific Couplings of Secondary and Tertiary Boronic Esters

2014

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“…Differentiation of the two carbonyls of 13 would render quaternary C10 chiral. The right-hand segment 10 may arise from (+)-citronellol ( 14 ); the tertiary C17 could be introduced through Myers asymmetric alkylation or sequential Aggarwal lithiation–borylation and Zweifel–Evans olefination …”

Section: Resultsmentioning

confidence: 99%

“…Although Myers’ alkylation chemistry provided an efficient means to establish the C17 stereochemistry, the tedious modifications after the alkylation significantly lowered the overall efficiency of the route described herein. Aggarwal and colleagues have developed lithiation–borylation chemistry for the construction of consecutive stereocenters and showcased its power by a series of elegant syntheses of natural products . Taking advantage of this method, we installed the tertiary C17 with good stereocontrol and minimized efforts of functional group manipulation (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

Total Synthesis of Aplysiasecosterol A

Zhang

Guo

et al. 2018

J. Am. Chem. Soc.

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Aplysiasecosterol A (1) is a structurally unusual 9,11-secosteroid isolated from the sea hare Aplysia kurodai. We have accomplished the first and asymmetric total synthesis of 1 in a convergent fashion. The left-hand segment bearing three adjacent stereocenters was constructed through desymmetrizing reduction, ketalization, and radical cyclization. A strategy of asymmetric 2-bromoallylation followed by spontaneous desymmetrizing lactolization enabled a more expeditious access to this segment. The right-hand segment was prepared through two different approaches: one featuring Myers alkylation and Suzuki-Miyaura coupling and the other relying upon Aggarwal lithiation-borylation and Zweifel-Evans olefination. The two fragments were coupled by a Reformatsky type reaction. The three consecutive stereocenters embedded in the central domain of 1 were generated by an iron-mediated, hydrogen atom transfer based radical cyclization reaction.

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“…An addition of the hydride catalyst to the alkene could occur rstly in the presence of the organoborane, furnishing "organoborate" intermediate I, 22 which has been recognized as a class of particularly versatile synthetic intermediates in organic synthesis. 23 Intermediate I could then undergo an intermolecular regioselective addition to organoborane-activated heteroarenes II leading to s H -adduct intermediates III and IV. Finally, by an elimination of the hydride anion, a Chichibabin-type-like process, 11 could occur with the assistance of the organoborane to furnish the expected alkylation product simultaneously regenerating the hydride catalyst to participate in the next catalytic cycle.…”

Section: Edge Article Chemical Sciencementioning

confidence: 99%