Science of Synthesis

Crisp, G. T., Science of Synthesis, (2003) 5, 524.

The hydroalumination of substituted prop-2-yn-1-ols, followed by the addition of electrophilic trialkylstannanes, provides ready access to a variety of functionalized Z-alkenylstannanes. For example, addition of lithium aluminum hydride to propargyl alcohol selectively affords the Z-alkenylaluminate ‌11‌, which can be reacted with tributyltrifluoromethylsulfonyloxy)stannane (X = OTf) to give (Z)-3-(tributylstannyl)prop-2-en-1-ol (‌12‌, R1 = H) in 80% yield (‌Scheme 6‌).[‌15‌] The hydroalumination of substituted prop-2-yn-1-ols can be used to prepare 3-substituted 3-(tributylstannyl)prop-2-en-1-ols ‌12‌ when tributylmethoxystannane (X = OMe) is used (lower yields are obtained with tributyltrifluoromethyl(sulfonyloxy)stannane or tributylchlorostannane) (‌Scheme 6‌).[‌16‌] Yields are in the range 13–74% for a wide variety of R1 groups (alkyl, aryl, heteroaryl, ethers) and triethylamine should be added to the solvents used for chromatographic purification of the products in order to prevent protiodestannylation.[‌16‌] An alternative method for the preparation of γ-hydroxyalkenylstannanes, such as ‌13‌, is to use dichlorobis(η5-cyclopentadienyl)titanium to catalyze the hydromagnesiation of a propargyl alcohol, with subsequent trapping of the alkenylmagnesium intermediate with tributylchlorostannane (‌Scheme 6‌).[‌17‌] This method relies on the coordination of the metal to the oxygen to control the regio- and stereochemistry of the final alkenylstannane.

‌Meeeee 8‌ Meeeeeeeeeeeeeee eee Meeeeeeeeeeeeeeee ee Meeeeeeee Meeeeeee[‌88‌–‌88‌]

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Meeeeeeeee eeeeeeeee ee M-eee-8-eeeeeeeeeeeeeeeeee (eeeeee ee eee eeeeeeeeeeeee ee eee-8-eeee eeee e eeeeeeeeeeeee) eeee eeeeee eeeeeeeee eee eeee eeeeeeeeeeeeeeeeeeeeee ee eee eeeeeeee ee e eeeeeeeee eeeeeeee ee (eeeeeeeeeeeeeee)eeeeee(MM) eeeee eee eeeeeeeeeeeee M-eeeeeeeeeeeeeee ‌88‌ ee eeeeeeeee eeeee (‌Meeeee 8‌).[‌88‌]

‌Meeeee 8‌ Meeeeeeeeeee ee Meeeeee Meeeeeeeee eee Meeeeee[‌88‌,‌88‌]

Meeeeeeeeeee Meeeeeeee

8-(8-Meeeeee)-8-(eeeeeeeeeeeeeee)eeee-8-ee-8-ee (‌88‌, M8 = 8-eeeeeee); Meeeeee Meeeeeeee:[‌88‌]

MeMMe (8.88 e, 8.8 eeee) eee eeeee ee e 8 M eeee ee MeMeM8 ee MMM (88.8 eM). Mee eeeeeee eee eeeeee ee 8°M, eeeeeeeee e eeee ee 8-(8-eeeeeee)eeee-8-ee-8-ee (8.8 e, 88.8 eeee) ee MMM (88 eM) eee eeeeee eeeee. Mee eeeeeeeee eeeeeee eee eeeeeee eee 8 e ee 8°M, MeMMe (8.8 eM) eee eeee eeeee, eee eee eeeeeee eee eeeeeee eee 88 eee eeeeeee eeeeeee. Mee eeeeeee eee eeee eeeeee ee 8°M eeee eeee, Me8MeMMe (88.8 eM, 88.8 eeee) eee eeeee, eee eee eeeeeee eee eeeeee ee e eeeeeeeeeeee (8°M). Meeee 8 e, MeMM (88 eM) eee eeeee, eee eee eeeeeee eee eeeeeee eee 8 e ee ee eee eeee eeeeee eeee M8M (888 eM). Mee eM eee eeeeeeeee eeeeeeee ee 8 ee eee eeeeeeee ee eee MMe eee eee eeeeeee eee eeeeeeeee eeee Me8M (8 × 888 eM). Mee eeeeeeee eeeeeeee eeeeeeee eeee eeeee (Me8MM8) eee eee eeeeeee eee eeeeeeeeee ee eeeee. Meeeeeeeeeeeee ee eee eeeeeee (eeeeee eee, eeeee eeeeeeeee eeeee/eeeeeee 88:8) eeee eee eeeeeee; eeeee: 88.88 e (88%).

References

Meeeeee Meeeeeeeeee

• 8.Meeeee-Meee, (8888) M 88e, 888.