Donald S. Matteson

Osmium tetroxide catalyzed hydroxylation of hindered olefins

Abstract Osmium tetroxide catalyzed hydroxylation of sterically hindered olefins proceeds efficiently with trimethylamine N-oxide as oxidizing agent in the presence of pyridine.

A stereocontrolled synthesis of Z and E terminal dienes from pinacol E-1-trimethylsilyl-1-propene-3-boronate

Pinacol E-1-trimethylsilyl-1-propene-3-boronate reacts with aldehydes to form (±)-(R*,S*)-3-trimethylsilyl-4-hydroxy-1-alkenes, which can be deoxysilylated stereoselectively to either 98% Z or 99% E 1,3-dienes, including the separate components of the red bollworm moth pheromone.

FUNCTIONAL GROUP COMPATIBILITIES IN BORONIC ESTER CHEMISTRY

Abstract Problems encountered in the chemistry of highly functionalized boronic esters are reviewed. These include β-eliminations of boron and an electronegative group, protodeboronations, and anomalous oxidations. Groups that appear to be particularly compatible with boronic esters or that lead to instability only in certain relationships are also discussed, including azido, alkoxy, cyano and carboxylic ester substituents.

Chloromethyl) lithium in an efficient conversion of carbonyl compounds to chlorohydrins or oxiranes

Abstract (Chloromethyl)lithium has been generated and captured in nearly quantitative yields by addition of n -butyllithium or methyllithium to mixtures of chloroiodomethane with aldehydes or ketones in THF at −78 °C. Immediate acidification yields chlorohydrins, delayed workup yields epoxides.

Boronic esters in asymmetric synthesis.

The authors work on (α-haloalkyl)boronic esters as reagents for asymmetric synthesis is reviewed. Diastereomeric ratios exceeding 1000 can be achieved with this chemistry, and ratios around 100 are commonplace. The method allows sequential installation of a series of stereocenters and tolerates a wide variety of suitably protected functional substituents. (α-Amidoalkyl)boronic acids include biochemically significant serine protease inhibitors, one of which is the clinically successful proteasome inhibitor bortezomib, used for treatment of multiple myeloma and mantle cell lymphoma.

Methanetetraboroni and methanetriboronic esters

Abstract Octamethyl methanetetraboronate, [(MeO) 2 B] 4 C, has been prepared in > 100 g batches by the reaction of dimethoxyboron chloride and carbon tetrachloride with lithium in tetrahydrofuran. Analogous reactions have yielded the methanetriboronic esters [(MeO) 2 B] 3 CH, [(MeO) 2 B] 3 C-C 6 H 5 , and [(MeO) 2 B] 3 C-CH 3 . and the methanediboronic esters [(MeO) 2 B] 2 CH 2 and [(MeO) 2 B] 2 CHC 6 H 5 . A preliminary survey of the properties of these compounds has been made.

A directed chiral synthesis of amino acids from boronic esters

Abstract Conversion of (s)-pinanediol (1S)-1-haloalkylboronates to (1R)-1-azido boronates, homologation with (dichloromethyl)lithium to 1-chloro-2-azido boronates, oxidation with sodium chlorite to the α-azido acids, and catalytic hydrogenation yielded L-amino acids, 92-96% enantiomeric excess.

Iodomethaneboronic esters and aminomethaneboronic esters

Abstract An efficient preparation of pinacol iodomethaneboronate and dibutyl iodomethaneboronate from the respective (phenylthio)methaneboronic esters has been devised, using the reaction with methyl iodide. Pinacol iodomethaneboronate reacts efficiently wit tertiary amines to form the crystalline quaternary ammonium salts. Dibutyl iodomethaneboronate reacts with excess piperidine or morpholine in ether to precipitate piperidine or morpholine hydriodide and yield the distillable piperidino- or morpholinomethaneboronic ester. Benzylamine failed to yield a stable product.

Lithium bis(ethylenedioxyboryl)methide and its reactions with carbonyl compounds and with the chlorotriphenyl derivatives of germanium, tin and lead

Transesterification of tris(dimethoxyboryl)methane, HC[B(OCH3)2]3, with ethylene glycol yielded tris(ethylenedioxyboryl)methane (I), HC(BO2C2H4)3 which with methyllithium in THF at −70°C precipitated lithium bis(ethylenedioxyboryl)methide (II), Li+ HC(BO2C2H4)2-. Reaction of II with Ph3MCl, where M = Ge, Sn, or Pb, gave Ph3MCH(BO2C2H4)2. The analogous 1,3-propanediol ester, Li+HC(BO2C3H6)2-, yielded Ph3MCH(BO2C3H6)2. Treatment of Ph3SnCH(BO2C2H4)2 with MeLi followed by Ph3SnCl gave (Ph3Sn)2CHBO2C2H4, showing that one B and one Sn atom are sufficient to stabilize a carbanion. Reaction of II with aldehydes gave high yields of 1-alkene-1-boronic esters, RCHCHBO2C2H4, with unexpectedly high stereoselectivity, 90–100% trans by NMR analysis. Aqueous work-up of these boronic esters yielded the boronic acids, RCHCHB (OH)2, which crystallized as the pure trans isomers. Ketones react with II in an analogous manner. The reaction with acetophenone was not stereospecific. Functional group compatibility has been demonstrated in condensations of II with 1,3-dichloroacetone, cinnamaldehyde, p-nitrobenzaldehyde, and p-dimethylaminobenzaldehyde. The trans geometry of the major isomer of CH3CHCHBO2C2H4 was proved by B-butylation with butyllithium followed by rearrangement with iodine and base to form cis-2-heptene, a sequence of known stereochemistry, and analogous structure proofs were carried out with cis-CH3CHCHBO2C2H4 and trans-C6H5CHCHBO2C2H4.

Alkene-1,1-diboronic esters from the condensation of triborylmethide anions with ketones or aldehydes☆

The triborylmethide ions, [(RO)2B]3C−, from the reaction of methyllithium with the methyl ester of methanetetraboronic acid, C[B(OMe)2]4, or the pinacol ester, C(BO2C2Me4)4, condense readily with ketones, R′2CO, to form alkene-1,1-diboronic esters, R′2CC[B(OR)2]2. The reaction is a general one and tolerates other functional groups, including α-chloro, carbethoxy, and tertiary amino substituents. Acetaldehyde and benzaldehyde also undergo the condensation. The alkene-1,1-diboronic esters are potentially useful synthetic intermediates. Their reactions include conversion to carboxylic acids by hydrogen peroxide, conversion to α-bromoalkeneboronic esters by bromine, and conversion to alkenyl-1,1-dimercuric chlorides by mercuric chloride and sodium acetate.