COP

Pd – Allylic Imidate Rearrangement OL03-5-1809

COP_OL03-5-1809

JACS03-125-12412

COP_JACS03-125-12412

OL07-9-5239

COP_OL07-09-5239_1

Method from OBC paper.

OBC10-8-3418

COP_OBC10-8-3418

Ring-closing metathesis with Grubbs I followed by Kharasch cyclisation.

JACS14-136-17302

COP_JACS14-136-17302

Rearrangement product incorrectly drawn as the S enantiomer in this paper. Correct R enantiomer drawn above.

 

Pd – Intramolecular aminopalladation JOC05-70-2859

COP_JOC05-70-2859

Tosylcarbamate substrates prepared from corresponding allylic alcohol and p-toluenesulfonyl isocyanate.

 

Pd – Intramolecular allylic substitution JOC10-75-7897

COP_JOC10-75-7897

No specific experimental for this reaction – quantity of solvent used not given.

 

Pd – [3,3]-Sigmatropic rearrangement of allyloxy substituted N-heterocycles OL10-12-260

COP_OL10-12-260

 

Pd – O-Allyl Carbamothioate Rearrangement OL08-10-1485

COP_OL08-10-1485

Reaction also performed at RT (67 h, 5 mol% with R1 = n-Pr, R2 = 1-azetinyl, 83% ee) and with 1 mol% cat (47 h, 40 oC, R1 = n-Pr, R2 = 1-azetinyl, 76% ee).

OL14-16-1252

COP_OL14-16-1252

Higher ee with R1 = n-Pr than R1 = Me (for which several examples with <80% ee). Stereospecific N to C aryl migration (#) in some instances resulted in an erosion of ee (slow reaction relative to allyllithium racemisation).

 

Pd – Allylic Aryl Ester Synthesis JACS10-132-15185 (communication JACS05-127-2866)

COP_JACS10-132-15185

Much lower yield (and reduced e.e.) with COP-Cl. Lower e.e. with (E)-trichloroacetimidates and also competative allylic imidate rearrangement. Reaction temperature of 38 oC with bulkier (slower) carboxylic acids and/or those with lower solubilities. Complete (branched) regioselectivity excepting #. Mechanistic investigations and a model for the basis of enentioselectivity is reported in JACS10-132-15192.

CC07-4164

COP_CC07-4164

Iterative methodology also extended to the synthesis of all four protected triol enantiomers containing three stereogenic centres. All reactions show essentially complete catalyst control. Methodology further demonstrated by the total synthesis of (+)-solistatin.

 

Pd – Allylic Aryl Ether Synthesis OL07-9-911

COP_OL07-9-911

COP-Cl as catalyst gives comparable ee but inferior rate. One example with a branched γ-substituent with R1 = Cy (R2 = 4-OAc, 90% ee, 30% yield, 96 h). R2 = NO2, CN and allyl did not result in product formation.

ASC09-351-3186

COP_ASC09-351-3186

COP-NHCOCCl3 prepared from COP-OAc and 2,2,2-trichloroacetamide in benzene at 80 oC (azeotropic removal of acetic acid). Use of COP-OAc in the representative reaction resulted in a 59:41 ratio of phenyl ether (91% ee) to allylic imidate rearrangement product. With COP-NHCOCCl3 the corresponding ratio is 92:8.

 

Pd – Enantioselective synthesis of 2-vinyl oxygen heterocycles JOC12-77-1961

COP_JOC12-77-1961_1

Use of COP-Cl instead of COP-OAc resulted in competitive allylic imidate rearrangement. A very low ee resulted from a corresponding Z substrate. Acetates rather than trichloroacetimidates may be used for the synthesis of 2-vinylchromanes resulting in similar enantioselectivities although with a higher catalyst loading (2 mol%) and with 1 eq. of KF as additive.