Science of Synthesis

Ley, S. V.; Milroy, L.-G.; Myers, R. M., Science of Synthesis, (2007) 29, 613.

General Introduction

The spiroacetal, which is more commonly referred to as a spiroketal, is a distinguished architectural feature of many simple and complex natural products with important and varying biological properties. They exist in a number of differing ring arrangements and some of the most abundant include [6,6]-, [6,5]-, and [5,5]-spiroketals. There is also an array of dispiroketal combinations found in many natural products (‌Scheme 1‌).

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‌Meeeee 8‌ Meeeeeeeeeeee eee Meeeeeeeeeeeeee ee Meeeeeeeeee[‌88‌–‌88‌]

Mee eeeeeeee eeeeee eee ee eeeeeeeee ee eeeee ee e eee eeeeeeeeeee eeeeeee eeeeeee eee eeee-eeeeee, eeeeeeeeee eeeeeeeee ee eee eeeeeeeeee M—M eeeeeee eee eee eeeeeeeeeee σ*-eeeeeee ee eeeee eeeeeeee eeeeeeeee eeeeee M—M eeeee eeeeeeeeeeee eee M—M—M eeeeeee eeeeee. Mee eee eeeeeeeeeee eeeeeeee eeeeeeeeeeee ee eeeeeeeee eeee eee eeeeeeeeee eeeeeeeee eee eee eeeeeeeeeee σ*-eeeeeee eee eeeeeeeeee eeeeeeeeeeeeee ee eee eeeeeee, eeeeeeee eee eeeeeee eeeeeee [‌Meeeee 8‌, eeeeeeeee (e)].[‌88‌–‌88‌]

‌Meeeee 8‌ Mee Meeeeeee Meeeee ee Meeeeeeeeee[‌88‌–‌88‌]

Me eee eeee ee eee eeeeeee eeeeeeeeee, eee eeee eeeeeeee eeeeeee eee ee eeeeeeeee eee eeee ee eeeeeeeee eee eeee eeeeeeeeeee eeeeeeeeeeeee (‌Meeeee 8‌). Mee eeeee–eeeeeeeeee [‌Meeeee 8‌, eeeeeeeee (e)] eee eeeeeeeeee–eeeeeeeeee eeeeeeeeeeee, eeee eeeeeeeeeeeee eeeeee eeeeeee ee eeee eeee eee eeeeee ee eeeeeeeee eeeeeeee eeeeeee. Meeeeeeeeee eeeee eeeeeeee eeeeeeeeeeeee ee eeeeeeeeee eee eeeee eeeeeeee ee ee “eee-eeeeeeee” eee eee eeee eeeeeee ee eeeeeeeeeeee eeeeeee, eeeeeeeeeeee eeeeee eeeeeee eeeeeeee.[‌88‌] Meee eeeeeeeee e eeeeeeeeeee eeeeeeeee eeeeeeeee ee eeeee ee eee eeeee eeeeeeee ee eee eeeee eeeeeeeeeeee eeeeeeeeee eeeee M—M eeee, eee eeee eeee eeeeeeee ee eeeee eee eeeeeeee eeeeeeee.[‌88‌] Me eeeeeee, eeee eeeeeeeee eeeeeeee eeee eeeee eee eeeeeeeee ee eeeeeeeeeee eeee eeeeeee eeeeeeee eeeeeeeeeeeee.

Me eeeee ee eeeeeeeeee eeeeeeee, eee eeeeeeeeeeeeeeee ee eeeeeeeeeee eeeeeeee eeee eee eeeeeeeee, eeeeeeeeee eeeee eeeeeeeeeeeeeee eeeeeeeeeee ee eee eeeee eeeeee eee ee eeeeeeeee ee eeeeeeeeeee. Meeee eeeee eee eee eeeeeee eeeeeee ee eeeeee eeee eeeeeeeeeeeeeeee ee eeeeeeeeee eeeeeeeee, eee eeeeeee' eeeeeeeeee ee eeee eee 88M MMM eeeeeeeeeeee eeeeee ee eee eeeeeeeeee eeeee eeeeee eeeeee (eeeeeeeee eeeee ee eee eeeee δ 88–888 ee MMMe8) ee eeeeeee.[‌88‌] Meeeeeeeeeeeeee [8,8]-eeeeeeeeeee ee eee 8′- eee/ee 8′-eeeeeeeee eeee eeeeeeeee eeeeeeee eeeeeee ee eeee 8M MMM (δ 8.8–8.8 ee MMMe8) eee 88M MMM (δ 88–88 ee MMMe8), eeeee eee eeeeee ee eeeeeeeee eeeee eeee eeeeeeeeeeee eeeeeee eeee-eeeee eeeeeeeeeee eeeeeeeeeeeee eeeeeee. Meeeeeeeeeeeeee eeeeeee eeeeeeeeeeeeee ee eeeeeeeeeeeeeee eeeeeee ee eeeeeeee eeeee MMM eeeeeeeeeeeee eeeeeeee eeee M-eee eeeeeeeeeeeeeee ee eee eeeeeeeee. Meee eeeeeee eeeeee ee eee eeee ee eeee eeeeeeeeeee eeeeeeeeee eeee eeeeeee. Me eeeeeee, eeeee eeeeeee eee ee eeeeeee ee eeeee-eeeee eeeeeeeeee eeee eeeeeee.

Meeeeeeee ee eee eeeee ee eeee eeeeee, ee eeeeee ee eeeee eeee eee eeee eeeeeeeeee eeeeeeeee ee eeeee-eeeeeeeeee eeeeeee eeeeeeee eeee eeeeeeee eeee eeee ee ee eeeeeeeee eee eeeeeeee eeeee ee eee eeeeeeeeee eeeeeeeee, eeeeee eeeee eee eeeeeeeeeeeeee eeeeeeee ee eeeee eeeeeeee. Meee eeeeee eeee ee eeeeeeeee eee eeee ee eeeee eeeeeee eee eeeee eee eeee eeeeeeeee ee eeeeeeeeee eeeeeeee ee eee eeeeeee ee eeee eeeeeee eeeeeeeee eeeeeee.

References