Stereospecific synthesis of (Z)-tamoxifen via carbometallation of alkynylsilanes

Miller, R. B.; Al-Hassan, M. I.

doi:10.1021/jo00212a023

Cited by 86 publications

(30 citation statements)

References 3 publications

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“…92–94 °C (Ref. : 95–97 °C); 1 H NMR (500 MHz, CDCl 3 ): δ =0.92 (t, J= 7.5 Hz, 3 H), 2.28 (s, 6 H), 2.45 (q, J= 7.5 Hz, 2 H), 2.64 (t, J= 5.7 Hz, 2 H), 3.92 (t, J= 5.7 Hz, 2 H), 6.52–6.60 (m, 2 H), 6.72–6.80 (m, 2 H), 7.07–7.13 (m, 3 H), 7.14–7.20 (m, 2 H), 7.21–7.29 (m, 3 H), 7.31–7.38 ppm (m, 2 H); 13 C NMR (125 MHz, CDCl 3 ): δ =13.7, 29.1, 46.0 (2C), 58.4, 65.8, 113.5 (2C), 126.1, 126.6, 128.0 (2C), 128.2 (2C), 129.6 (2C), 129.8 (2C), 132.0 (2C), 135.6, 138.4, 141.4, 142.5, 143.9, 156.9 ppm; IR (neat):

\overset{ν}{true}

max =1609, 1510, 1443, 1287, 1244, 1175, 1030, 966, 818, 775, 768, 698 cm −1 ; HRMS (ESI): m / z : calcd for C 26 H 29 NO: 372.2327 [ M +Na] + ; found: 372.2315.…”

Section: Methodsmentioning

confidence: 99%

Divergent Synthetic Access toE- andZ-Stereodefined All-Carbon-Substituted Olefin Scaffolds: Application to Parallel Synthesis of (E)- and (Z)-Tamoxifens

et al. 2017

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A highly substrate‐general synthesis of all‐carbon‐substituted E‐ and Z‐stereodefined olefins is performed. The method comprises two sets of parallel and stereocomplementary preparations of (E)‐ and (Z)‐α,β‐unsaturated esters involving two robust and distinctive reactions: 1) stereocomplementary enol tosylations using readily available TsCl/diamine/(LiCl) base reagents, and 2) stereoretentive Negishi cross‐coupling using the catalysts [Pd(dppe)Cl2] (for E) and [Pd(dppb)Cl2] (for Z). The present parallel approach is categorized as both type I (convergent approach: 16 examples, 56–87 % yield) and type II (divergent approach: 18 examples, 70–95 % yield). The obtained (E)‐ and (Z)‐α,β‐unsaturated ester scaffolds are successfully transformed into various E‐ and Z‐stereodefined known and novel olefins (8×2 derivatization arrays). As a demonstration, application to the parallel synthesis of both (E)‐ and (Z)‐tamoxifens, a representative motif of all‐carbon‐substituted olefins, is accomplished in a total of eight steps with an overall yield of 58 % (average 93 %) and 57 % (average 93 %), respectively.

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\overset{ν}{true}

max =1609, 1510, 1443, 1287, 1244, 1175, 1030, 966, 818, 775, 768, 698 cm −1 ; HRMS (ESI): m / z : calcd for C 26 H 29 NO: 372.2327 [ M +Na] + ; found: 372.2315.…”

Section: Methodsmentioning

confidence: 99%

Divergent Synthetic Access toE- andZ-Stereodefined All-Carbon-Substituted Olefin Scaffolds: Application to Parallel Synthesis of (E)- and (Z)-Tamoxifens

et al. 2017

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“…In general, 1,1‐diborylalkenes can undergo stereoselective cross‐coupling with aryl iodides to afford the corresponding ( E )‐alkenylboronates as single isomers. Subsequent coupling provides a completely stereocontrolled access to triarylated alkenes . Applying this concept, Hiyama and co‐workers developed a stereocontrolled approach to 1,1,2‐triaryl‐1‐alkenes based on sequential cross‐coupling of 1,1‐diborylalkenes (Scheme a).…”

Section: Reactivity Of 11‐diborylalkenesmentioning

confidence: 99%

Access to 1,1‐Diborylalkenes and Concomitant Stereoselective Reactivity

2018

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Gem‐diborylalkenes have emerged as efficient reagents for selective cross‐coupling reactions, reduction approaches and Michael additions. The synthesis of 1,1‐diborylalkenes involves condensation of polyborated compounds with aldehydes or ketones followed by B–O elimination, geminal diboration of 1,1‐dihaloalkenes, 1‐haloalkenes or terminal alkynes, dehydrogenative borylation of alkenes, borylation of alkynylboronates and hydroboration of alkynylboronates. These new sets of reactions are general for a wide range of substrates and they can be understood to have complementary mechanisms.

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“…Finally, the synthesis of tetraarylated olefin 8 bearing four different aryl groups was carried out through sequential transformations by utilizing the remaining silyl group. With Br 2 and NaOMe,81 the silyl group in 6 was converted to the corresponding bromide 7 (Scheme ). It is noteworthy that this bromodesilylation proceeded with an inversion of stereochemistry,82 which was confirmed by structural determination of its cross‐coupled product 8 .…”

Section: Silaboration Of An Alkynylboronatementioning

confidence: 99%

Synthesis of Multisubstituted Olefins through Regio‐ and Stereoselective Addition of Interelement Compounds Having B–Si, B–B, and Cl–S Bonds to Alkynes, and Subsequent Cross‐Couplings

Iwasaki¹,

Nishihara²

2016

The Chemical Record

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Multisubstituted olefins are fundamental motifs in organic compounds. In this account, we describe the synthesis of organic molecules bearing an olefinic moiety by the transition-metal-catalyzed regio- and stereoselective addition of a variety of interelement compounds to alkynes. Regio- and stereoselective silaboration, diborylation, and chlorothiolation have been achieved by using the transition-metal catalysts. The subsequent cross-coupling reactions of the boron-containing alkenes to install various aryl groups afforded the corresponding tri- and tetraarylated olefins. This account describes our research on the highly regio- and stereoselective synthesis of multifunctionalized olefins such as tetraarylethenes with four different aryl groups.

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Stereospecific synthesis of (Z)-tamoxifen via carbometallation of alkynylsilanes

Cited by 86 publications

References 3 publications

Divergent Synthetic Access toE- andZ-Stereodefined All-Carbon-Substituted Olefin Scaffolds: Application to Parallel Synthesis of (E)- and (Z)-Tamoxifens

Divergent Synthetic Access toE- andZ-Stereodefined All-Carbon-Substituted Olefin Scaffolds: Application to Parallel Synthesis of (E)- and (Z)-Tamoxifens

Access to 1,1‐Diborylalkenes and Concomitant Stereoselective Reactivity

Synthesis of Multisubstituted Olefins through Regio‐ and Stereoselective Addition of Interelement Compounds Having B–Si, B–B, and Cl–S Bonds to Alkynes, and Subsequent Cross‐Couplings

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