Highly Selective Conversion of Terminal Olefins into Aldehydes

Brown, Herbert C.; Kulkarni, Surendra U.; Rao, C. Gundu

doi:10.1055/s-1980-28956

Cited by 48 publications

(11 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To continue the synthesis, alkene 20 was hydroborated with disiamylborane to regioselectively generate primary alcohol 21 , which then was cleanly oxidized under Swern conditions to yield aldehyde 22 (Scheme ). Addition of ethynylmagnesium bromide to aldehyde 22 was not particularly stereoselective, affording a chromatographically separable 2/1 mixture of ( S )-propargyl alcohol 23 and ( R )-alcohol 24 , respectively.…”

Section: Resultsmentioning

confidence: 99%

Application of a Stereospecific Intramolecular Allenylsilane Imino Ene Reaction to Enantioselective Total Synthesis of the 5,11-Methanomorphanthridine Class of Amaryllidaceae Alkaloids

Jin

Weinreb

1997

J. Am. Chem. Soc.

View full text Add to dashboard Cite

Enantioselective total syntheses of the pentacyclic 5,11-methanomorphanthridine Amaryllidaceae alkaloids (−)-montanine (1), (−)-coccinine (2), and (−)-pancracine (3) were accomplished using an intramolecular concerted pericyclic allenylsilane imino ene cycloaddition as a key step. These complex natural products were constructed starting from readily available enantiomerically pure epoxy alcohol 15 which was converted to allenylsilane aldehyde 28 via an efficient nine-step sequence. The imine generated from aldehyde 28 and iminophosphorane 47 underwent a stereospecific thermal imino ene reaction to afford key intermediate cis aminoalkyne 49. It was possible to transform this compound via Lindlar hydrogenation followed by an intramolecular Heck reaction to seven-membered ring tetracycle 51. This olefinic intermediate could be functionalized through its epoxide to yield α-hydroxymethyl intermediate 54, and then pentacyclic alcohol 64. Procedures were then developed to convert this material to the enantiomerically pure alkaloids 1−3. A formal enantioselective total synthesis of (−)-brunsvigine (4) was also achieved via triol 72.

show abstract

Section: Resultsmentioning

confidence: 99%

Application of a Stereospecific Intramolecular Allenylsilane Imino Ene Reaction to Enantioselective Total Synthesis of the 5,11-Methanomorphanthridine Class of Amaryllidaceae Alkaloids

Jin

Weinreb

1997

J. Am. Chem. Soc.

View full text Add to dashboard Cite

show abstract

“…In building the 5.6.5. spiro bicyclic ring system, we initially envisioned applying the protocol of Brown et al. , for the oxidation of terminal olefins to their corresponding aldehydes to 5 . As outlined in Scheme , hydroboration of 5 followed by oxidation with pyridinium chlorochromate gave the desired aldehyde 11 in modest yields (25−30%).…”

Section: Synthesismentioning

confidence: 99%

Design, Synthesis, and Dopamine Receptor Modulating Activity of Spiro Bicyclic Peptidomimetics ofl-Prolyl-l-leucyl-glycinamide

et al. 1999

View full text Add to dashboard Cite

In the present study, the synthesis of the 5.5.6. and 5.6.5. spiro bicyclic lactam PLG peptidomimetics, compounds 3 and 4, respectively, was undertaken. These peptidomimetics were designed to examine the following: (1) the effect that changing the size of the thiazolidine and lactam ring systems would have on the ability of these systems to mimic the type-II beta-turn and (2) the effect that these structural perturbations would have on the ability of the peptidomimetics to modulate dopamine receptors. Through the use of the [3H]spiroperidol/N-propylnorapomorphine (NPA) dopamine D2 receptor competitive binding assay, 3 and 4, at a concentration of 100 nM, decreased the dissociation constant of the high-affinity state of the dopamine receptor for the agonist. These effects were observed when either Gpp(NH)p was absent or present and they were comparable to those produced by PLG at a concentration of 1 microM. Peptidomimetics 3 and 4 also increased the percentage of D2 receptors that existed in the high-affinity state. Even with Gpp(NH)p present, 3 and 4 were able to return the RH/RL ratios to values observed in the respective controls where Gpp(NH)p was absent. Furthermore, both peptidomimetics were able to attenuate the Gpp(NH)p-induced shift to the low-affinity state to a greater extent than PLG. Peptidomimetics 3 and 4 were evaluated in vivo as modulators of apomorphine-induced rotational behavior in the 6-hydroxydopamine-lesioned rat model of hemiparkinsonism, and each affected the rotational behavior in a bell-shaped dose-response relationship producing increases of 95 +/- 31% (0.01 mg/kg, ip) and 88 +/- 14% (0.001 mg/kg, ip), respectively. In comparison, the previously reported 5.5.5. spiro bicyclic lactam 2 increased rotational behavior by 25 +/- 11% (0.01 mg/kg, ip).

show abstract

“…The combined extracts were washed with water (10 ml) and saturated brine (10 ml) then dried and evaporated to leave the deuteriated acid (20) (0.126 g, 9973, m.p. 136138°C; 6, 2.21 (3 H, br s, 4-CH3) and 7.33 (1 H, m, 5-H), m/z 127 (M', loo%), 110 (49), 81 (28), and 57 (24).…”

Section: -Methylfuran-3-carborylicmentioning

confidence: 99%

“…(1 H, m, :CH); m/z 208 (M', 3473, 152 (57), 137 (13), 124 (13), 112 (36), 83 (24), and 57 (100) (Found: C, 74.7; 9.8. C1 3H20O2 requires C, 75.0; H, 9.6%).…”

Section: -Methyl-3-( 2-methylpropoxy)-5-(prop-2-enyl)cyczopent-2-mentioning

confidence: 99%

“…The resulting mixture was extracted with ether (3 x 10 ml) and the combined extracts were washed with water (20 ml) then dried and evaporated to give the alcohol (%a) (0.15 g, 84%), as a colourless oil, b.p. 120-1 30 "C at 0.1 mmHg; A , , , 278 nm; vmsx 3 500 and 1 700 cm-'; tjH 0.07 (3 H, s, CH,Si), 0.09 (3 H, s, CH,Si), 0.91 (9 H, s, SiCMe,), 1.30-1.59 (4 H, m), 1.64 (3 H, m, 2'-CH,), 1.95-2.07 (1 H, m), 2.14 (3 H, d, J 1.2, 4-CH,), 2.99-3.05 (1 H, br s, OH), 3.50 (2 H, dt, J 13 and 7, CH2CH20), 3.50-3.56 (2 H, my CH20), 3.79 (3 H, s, OCH,), 4.65 (1 H, br t, J 7, 3'-H), and 7.15 ( 1 H, q, J 1.2, 5-H) (primes refer to the cyclopentenyl unit) (major diastereoisomer); m/z 408 ( M ', 13%), 393 (20), 349 (44), 276 (9), 259 (ll), 245 (24), 227 (41), 199 (26), and 75 (100) (Found: C, 64.9; H, 8.9. C22H3605Si requires C, 64.7; H, 8.8%).…”

Section: -~3-(dimethyl-t-butylsilyloxy)-5-(3-hydroxypropyl)-2-methylc...mentioning

confidence: 99%

See 1 more Smart Citation

A total synthesis of the guaiane furanosesquiterpene (±)-gnididione, a metabolite of Gnidia latifolia

Buttery¹,

Cameron²,

Dell³

et al. 1990

J. Chem. Soc., Perkin Trans. 1

View full text Add to dashboard Cite

Highly Selective Conversion of Terminal Olefins into Aldehydes

Cited by 48 publications

References 0 publications

Application of a Stereospecific Intramolecular Allenylsilane Imino Ene Reaction to Enantioselective Total Synthesis of the 5,11-Methanomorphanthridine Class of Amaryllidaceae Alkaloids

Application of a Stereospecific Intramolecular Allenylsilane Imino Ene Reaction to Enantioselective Total Synthesis of the 5,11-Methanomorphanthridine Class of Amaryllidaceae Alkaloids

Design, Synthesis, and Dopamine Receptor Modulating Activity of Spiro Bicyclic Peptidomimetics ofl-Prolyl-l-leucyl-glycinamide

A total synthesis of the guaiane furanosesquiterpene (±)-gnididione, a metabolite of Gnidia latifolia

Contact Info

Product

Resources

About