WE recently reported that the alkylation reactions of the dianion derived from the acetylenic glycinate (la), with a variety of electrophiles, including a Michael acceptor, proceed invariably in a regiospecific sense to afford acetyl- enic and not allenic products.1 Such regiospecificity, ... SiMe, I i. me '1' ii. RZX @ ... When the t-butyl carbamate (3) is treated with an excess of lithium di-isopropylamide (LDA) or t-butyl-lithium in the presence of tetramethylethylenediamine at - 78 "C, the ...
