Tethered Silanoxyiodination of Alkenes

Abstract

<div>We present the first examples of tethered silanoxyiodination reactions of allylic alcohols. The products are useful</div><div>silanediol organoiodide synthons and are formed with high regioselectivity and diastereocontrol. The reaction is scalable greater than 10-fold without loss of yield or selectivity. Furthermore, the products are starting materials for further transformations, including de-iodination, C–N bond installation, epoxide synthesis, and de-silylation. DFT calculations provide a basis for understanding the exquisite 6-endo selectivity of this silanoxyiodination reaction and show that the observed products are both kinetically and thermodynamically preferred.</div>

Unusual Covalent Tethers for Precise Amino-Alcohol Syntheses: Ring Opening of Epoxides by Pendant Sulfamates and Sulfamides

“…The ring-opening of epoxides is an attractive method for the assembly of alcohol-containing stereoarrays. [3][4][5][6][7] Our laboratory has a programmatic focus on the use of unusual nucleophiles for the ring-opening of both transient [8][9][10][11][12][13] and stable electrophiles. 14,15 As part of this line of inquiry, it occurred to us that a ring-opening of epoxides by pendant sulfamates and sulfamides would offer predictable access to vicinal amino-alcohols and would complement our previous efforts with intramolecular cleavage of aziridines by di-tert-butyl-silanol auxiliaries.…”

Hydroxyselenylation and Tethered Silanoxyselenylation of Allylic Silanols

“…[3][4][5][6][7][8][9][10] Our laboratory has provided the first examples of the use of silanol tethers for the intramolecular ring-opening of both transient and stable electrophiles. [11][12][13][14] Organoselenides have many attractive properties that make them complementary to organomercurials and organohalides. [15][16][17] Unlike organohalides, organoselenides are stable to most common synthetic reactions, including hydrolysis, nucleophilic substitution, reduction, and Swern-type oxidations.…”

Highly Stereospecific Cyclizations of Homoallylic Silanols

“…[13][14][15][16][17][18][19] Our laboratory has a programmatic focus on the development of the di-tert-butyl-silanol auxiliary for alkene manipulation reactions. [20][21][22][23][24][25] We envisioned a new method for the construction of C-O bonds via the intramolecular interception of a palladium π-allyl species with a pendant di-tert-butylsilanol functional group (Scheme 1). Based on our previous work as well as that of others, [26][27][28][29][30][31] we expected such a reaction to be highly chemo-, regio-, and diastereoselective.…”