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A simple protocol for the C1 arylation of tetrahydroisoquinolines with aryl Grignard reagents via diethyl azodicarboxylate (DEAD) mediated oxidative C-H activation under metal-free conditions has been developed. The target compounds, including some naturally occurring alkaloids, were obtained in moderate to good yields. [ABSTRACT FROM AUTHOR]

Direct cross-coupling between N-methyltetrahydroisoquinolines and alkynes using CuI-DEAD is presented. It affords the regioselective C-1-alkynylated products in good yield. This regioselectivity is in contrast to the results reported earlier in the reaction of N,N-dimethylbenzyl amine where the N-methyl alkynylated product was formed exclusively or predominantly. The C-1-substituted propargylic isoquinolines were easily reduced to phenethylisoquinolines with Pd/C. This reaction sequence provides a short route to synthesize methopholine, homolaudanosine and other phenethylisoquinoline alkaloids. [ABSTRACT FROM AUTHOR]

The novel procedure renders possible the direct C-4 arylation of the tetrahydroisoquinoline skeleton. [ABSTRACT FROM AUTHOR]

The method is applied to the synthesis of cryptostyline II (IXa) and cryptostyline III (IXb). [ABSTRACT FROM AUTHOR]

Copper-catalyzed direct cross-coupling of isoquinolines (I) with alkynes gives the C-1 alkynylation products selectively. [ABSTRACT FROM AUTHOR]