Bromo-1,3-bis 4-methylphenyl sulfonyl-4,5-diphenyl-1,3,2-diazaborolidine

Related Reagents. 4-phenyl-1,2,4-triazoline-3,5-dione (-)-(ot)-(methylbenzyl) triazolinedione (dehydroabiethyl) triazoline-dione (+)-tetra-2-pinanylborane chiral platinum complexes. 

Alternate Name 2-bromo-4,5-diphenyl-l,3-bis-(toluene-4-sulf-onyl)-[ 1,3,2]diazaborolidine. 

Handling, Storage, and Precautions highly moisture-sensitive should be prepared immediately prior to use under inert atmosphere, preferably using standard Schlenk techniques (use of a glove box not required). Best results are obtained when fresh solutions of BBrs are used. 

Reactions of achiral aldehydes and homochiral stannanes exhibit stereoselectivity which is predominantly dictated by the chiral auxiliary 1 if the pre-existing asymmetry of the stannane is located at least two carbons or more (3) from the reactive allyl unit (eqs 2-4).  

Achiral stannanes undergo reactions with aldehydes bearing a-asymmetry, and provide examples of matched diastereoselec-tivity with respect to 1 (eq 5), as well as cases of mismatched diastereoselection of these controlling factors (eq 6).  

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General. Chiral 2-bromo-l,3-bis(4-methylphenyl sulfonyl)-4,5-diphenyl- 1,3,2-diazaborolidine (1) is used to control the stereochemistry of enantioselective aromatic Claisen rearrangements, allylations of aldehydes, aldol reactions, and formation of chiral propa-l,2-dienyl and propargyl alcohols. Included is the discussion of both the R,R) and the (5,5) chiral controllers. 

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